Comcast (CMCSA) 10-K 31 Jan 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Jun. 30, 2018
Document And Entity Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	cmcsa
Entity Registrant Name	COMCAST CORP
Entity Central Index Key	1,166,691
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Public Float		$ 149,068
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
NBCUniversal Media LLC [Member]
Document And Entity Information [Line Items]
Entity Registrant Name	NBCUniversal Media, LLC
Entity Central Index Key	902,739
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Public Float		$ 0
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Class A Common Stock [Member]
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding	4,516,518,147
Class B Common Stock [Member]
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding	9,444,375

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue	$ 94,507	$ 85,029	$ 80,736
Costs and Expenses:
Programming and production	29,692	25,355	24,348
Other operating and administrative	28,094	25,449	23,840
Advertising, marketing and promotion	7,036	6,519	6,291
Depreciation	8,281	7,914	7,464
Amortization	2,736	2,216	1,962
Other operating gains	(341)	(442)	0
Total costs and expenses	75,498	67,011	63,905
Operating income	19,009	18,018	16,831
Interest expense	(3,542)	(3,086)	(2,942)
Investment and other income (loss), net	(225)	421	437
Income before income taxes	15,242	15,353	14,326
Income tax (expense) benefit	(3,380)	7,569	(5,298)
Net income	11,862	22,922	9,028
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock	131	187	350
Net income attributable to Comcast Corporation	$ 11,731	$ 22,735	$ 8,678
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 2.56	$ 4.83	$ 1.80
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	2.53	4.75	1.78
Dividends declared per common share (in dollars per share)	$ 0.76	$ 0.63	$ 0.55
NBCUniversal Media LLC [Member]
Revenue	$ 35,895	$ 32,950	$ 31,398
Costs and Expenses:
Programming and production	16,330	14,276	14,424
Other operating and administrative	7,980	7,687	7,033
Advertising, marketing and promotion	2,952	2,806	2,778
Depreciation	1,001	994	861
Amortization	1,107	1,047	944
Other operating gains	(141)	(337)	0
Total costs and expenses	29,229	26,473	26,040
Operating income	6,666	6,477	5,358
Interest expense	(489)	(727)	(595)
Investment and other income (loss), net	(521)	(144)	24
Income before income taxes	5,656	5,606	4,787
Income tax (expense) benefit	(351)	(392)	(305)
Net income	5,305	5,214	4,482
Less: Net income attributable to noncontrolling interests	68	134	311
Net income attributable to Comcast Corporation	$ 5,237	$ 5,080	$ 4,171

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 11,862	$ 22,922	$ 9,028
Unrealized gains (losses) on marketable securities, net of deferred taxes	1	(42)	0
Deferred gains (losses) on cash flow hedges, net of deferred taxes	50	60	(60)
Amounts reclassified to net income:
Realized (gains) losses on marketable securities, net of deferred taxes	0	(1)	(1)
Realized (gains) losses on cash flow hedges, net of deferred taxes	(6)	(37)	92
Employee benefit obligations, net of deferred taxes	7	41	213
Currency translation adjustments, net of deferred taxes	(916)	147	102
Comprehensive income	10,998	23,090	9,374
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock	131	187	350
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(41)	81	74
Comprehensive income attributable to Comcast Corporation	10,908	22,822	8,950
NBCUniversal Media LLC [Member]
Net income	5,305	5,214	4,482
Unrealized gains (losses) on marketable securities, net of deferred taxes	0	(233)	0
Deferred gains (losses) on cash flow hedges, net of deferred taxes	3	(13)	24
Amounts reclassified to net income:
Employee benefit obligations, net of deferred taxes	14	112	15
Currency translation adjustments, net of deferred taxes	(16)	189	112
Comprehensive income	5,306	5,269	4,633
Less: Net income attributable to noncontrolling interests	68	134	311
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(41)	81	74
Comprehensive income attributable to Comcast Corporation	$ 5,279	$ 5,054	$ 4,248

Consolidated Statement of Com_2

Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrealized gains (losses) on marketable securities, deferred taxes	$ (1)	$ 25	$ (1)
Deferred gains (losses) on cash flow hedges, deferred taxes	(3)	(35)	35
Realized (gains) losses on marketable securities, deferred taxes	0	1	1
Realized (gains) losses on cash flow hedges, deferred taxes	(4)	22	(54)
Employee benefit obligations, deferred taxes	(2)	(24)	(125)
Currency translation adjustments, deferred tax	$ 9	$ (40)	$ (14)

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 11,862	$ 22,922	$ 9,028
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other operating gains	10,676	9,688	9,426
Share-based compensation	826	751	640
Noncash interest expense (income), net	364	272	230
Net (gain) loss on investment activity and other	576	(194)	19
Deferred income taxes	290	(10,646)	1,434
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Current and noncurrent receivables, net	(802)	(869)	(649)
Film and television costs, net	(395)	(197)	(501)
Accounts payable and accrued expenses related to trade creditors	(394)	173	378
Other operating assets and liabilities	1,294	(639)	(314)
Net cash provided by operating activities	24,297	21,261	19,691
Investing Activities
Capital expenditures	(9,774)	(9,550)	(9,135)
Cash paid for intangible assets	(1,935)	(1,605)	(1,552)
Acquisitions and construction of real estate properties	(143)	(418)	(428)
Construction of Universal Beijing Resort	(460)	(71)	(22)
Acquisitions, net of cash acquired	(38,219)	(532)	(3,929)
Proceeds from sales of businesses and investments	141	150	218
Purchases of investments	(1,257)	(2,292)	(1,697)
Deposits	0	0	(1,749)
Other	793	785	29
Net cash provided by (used in) investing activities	(50,854)	(13,533)	(18,265)
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	379	(1,905)	1,790
Proceeds from borrowings	44,781	11,466	9,231
Repurchases and repayments of debt	(8,798)	(6,364)	(3,052)
Repurchases of common stock under repurchase program and employee plans	(5,320)	(5,435)	(5,352)
Dividends paid	(3,352)	(2,883)	(2,601)
Purchase of Universal Studios Japan noncontrolling interests	0	(2,299)	0
Issuances of common stock	0	0	23
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	(277)	(252)	(253)
Other	(273)	100	(220)
Net cash provided by (used in) financing activities	27,140	(7,572)	(434)
Impact of foreign currency on cash, cash equivalents and restricted cash	(245)	0	0
Increase (decrease) in cash, cash equivalents and restricted cash	338	156	992
Cash, cash equivalents and restricted cash, beginning of year	3,571	3,415	2,423
Cash, cash equivalents and restricted cash, end of year	3,909	3,571	3,415
NBCUniversal Media LLC [Member]
Operating Activities
Net income	5,305	5,214	4,482
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other operating gains	1,967	1,704	1,805
Net (gain) loss on investment activity and other	689	428	87
Deferred income taxes	(39)	2	89
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Current and noncurrent receivables, net	(452)	(594)	(502)
Film and television costs, net	35	(199)	(509)
Accounts payable and accrued expenses related to trade creditors	57	(43)	51
Other operating assets and liabilities	341	564	(606)
Net cash provided by operating activities	7,903	7,076	4,897
Investing Activities
Capital expenditures	(1,730)	(1,502)	(1,452)
Cash paid for intangible assets	(448)	(295)	(283)
Note receivable from Comcast	(2,054)	0	0
Construction of Universal Beijing Resort	(460)	(71)	(22)
Acquisitions, net of cash acquired	(80)	(140)	(205)
Proceeds from sales of businesses and investments	70	45	109
Purchases of investments	(587)	(490)	(290)
Other	(51)	586	(90)
Net cash provided by (used in) investing activities	(5,340)	(1,867)	(2,233)
Financing Activities
Proceeds from borrowings	692	3,948	0
Repurchases and repayments of debt	(438)	(3,498)	(1,565)
Proceeds from (repayments of) borrowings from Comcast, net	(1,777)	(872)	928
Distributions to member	(1,627)	(1,968)	(1,606)
Distributions to noncontrolling interests	(205)	(209)	(210)
Purchase of Universal Studios Japan noncontrolling interests	0	(2,299)	0
Other	(121)	79	356
Net cash provided by (used in) financing activities	(3,476)	(4,819)	(2,097)
Increase (decrease) in cash, cash equivalents and restricted cash	(913)	390	567
Cash, cash equivalents and restricted cash, beginning of year	2,377	1,987	1,420
Cash, cash equivalents and restricted cash, end of year	$ 1,464	$ 2,377	$ 1,987

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 3,814	$ 3,428
Receivables, net	11,104	8,834
Programming rights	3,746	1,613
Other current assets	3,184	2,468
Total current assets	21,848	16,343
Film and television costs	7,837	7,087
Investments	7,883	6,931
Property and equipment, net	44,437	38,470
Franchise rights	59,365	59,364
Goodwill	66,154	36,780
Other intangible assets, net	38,358	18,133
Other noncurrent assets, net	5,802	4,354
Total assets	251,684	187,462
Current Liabilities:
Accounts payable and accrued expenses related to trade creditors	8,494	6,908
Accrued participations and residuals	1,808	1,644
Deferred revenue	2,182	1,687
Accrued expenses and other current liabilities	10,721	6,620
Current portion of long-term debt	4,398	5,134
Total current liabilities	27,603	21,993
Long-term debt, less current portion	107,345	59,422
Deferred income taxes	27,589	24,259
Other noncurrent liabilities	15,329	10,972
Commitments and contingencies
Redeemable noncontrolling interests	1,316	1,357
Equity:
Preferred stock—authorized, 20,000,000 shares; issued, zero	0	0
Common stock	54	55
Additional paid-in capital	37,461	37,497
Retained earnings	41,983	38,202
Treasury stock, 872,791,028 Class A common shares	(7,517)	(7,517)
Accumulated other comprehensive income (loss)	(368)	379
Total Comcast Corporation shareholders’ equity	71,613	68,616
Noncontrolling interests	889	843
Total equity	72,502	69,459
Total liabilities and equity	251,684	187,462
NBCUniversal Media LLC [Member]
Current Assets:
Cash and cash equivalents	1,444	2,347
Receivables, net	7,293	6,967
Programming rights	1,323	1,606
Note receivable from Comcast	2,054	0
Other current assets	1,133	1,037
Total current assets	13,247	11,957
Film and television costs	7,292	7,082
Investments	1,680	1,816
Property and equipment, net	13,189	11,346
Goodwill	24,118	23,989
Intangible assets, net	13,666	13,306
Other noncurrent assets, net	1,822	1,804
Total assets	75,014	71,300
Current Liabilities:
Accounts payable and accrued expenses related to trade creditors	1,933	1,663
Accrued participations and residuals	1,808	1,644
Program obligations	965	745
Deferred revenue	1,118	1,457
Accrued expenses and other current liabilities	2,195	2,394
Note payable to Comcast	54	1,831
Current portion of long-term debt	151	198
Total current liabilities	8,224	9,932
Long-term debt, less current portion	12,731	12,275
Accrued participations, residuals and program obligations	1,712	1,490
Other noncurrent liabilities	5,177	4,153
Commitments and contingencies
Redeemable noncontrolling interests	389	409
Equity:
Member’s capital	45,618	42,148
Accumulated other comprehensive income (loss)	254	(20)
Total NBCUniversal member’s equity	45,872	42,128
Noncontrolling interests	909	913
Total equity	46,781	43,041
Total liabilities and equity	75,014	71,300
Class A Common Stock [Member]
Equity:
Common stock	54	55
Class B Common Stock [Member]
Equity:
Common stock	$ 0	$ 0

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Class A Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	7,500,000,000	7,500,000,000
Common stock, shares issued (in shares)	5,389,309,175	5,507,854,670
Common stock, shares outstanding (in shares)	4,516,518,147	4,635,063,642
Treasury stock (in shares)	872,791,028	872,791,028
Class B Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	9,444,375	9,444,375
Common stock, shares outstanding (in shares)	9,444,375	9,444,375

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Redeemable Noncontrolling Interests And Redeemable Subsidiary Preferred Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock at Cost [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	NBCUniversal Media LLC [Member]	NBCUniversal Media LLC [Member]Redeemable Noncontrolling Interest [Member]	NBCUniversal Media LLC [Member]Member's Capital [Member]	NBCUniversal Media LLC [Member]Accumulated Other Comprehensive Income (Loss) [Member]	NBCUniversal Media LLC [Member]Noncontrolling Interest [Member]	Class A Common Stock [Member]Common Stock [Member]	Class B Common Stock [Member]Common Stock [Member]
Beginning Balance at Dec. 31, 2015	$ 53,978		$ 38,490	$ 21,413	$ (7,517)	$ (174)	$ 1,709						$ 57	$ 0
Beginning Balance at Dec. 31, 2015								$ 34,303		$ 32,834	$ (212)	$ 1,681
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation plans	770		770
Repurchases of common stock under repurchase program and employee plans	(5,376)		(999)	(4,376)									(1)
Employee stock purchase plans	156		156
Dividends declared / Distributions to member	(2,656)			(2,656)				(1,606)		(1,606)
Other comprehensive income (loss)	346					272	74	151			77	74
Contributions from (distributions to) noncontrolling interests, net	(134)						(134)	(148)				(148)
Contribution from member								3,655		3,566		89
Other	144		(187)	6			325	87		(71)		158
Net income	8,935			8,678			257	4,433		4,171		262
Ending Balance at Dec. 31, 2016	56,163		38,230	23,065	(7,517)	98	2,231						56	0
Ending Balance at Dec. 31, 2016								40,875		38,894	(135)	2,116
Beginning Balance at Dec. 31, 2015		$ 1,221							$ 372
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions from (distributions to) noncontrolling interests, net		(16)							(59)
Other		148							168
Net income		93							49
Ending Balance at Dec. 31, 2016		1,446							530
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation plans	554		554
Repurchases of common stock under repurchase program and employee plans	(5,456)		(832)	(4,623)									(1)
Employee stock purchase plans	190		190
Dividends declared / Distributions to member	(2,975)			(2,975)				(1,968)		(1,968)
Other comprehensive income (loss)	168					87	81	55			(26)	81
Contributions from (distributions to) noncontrolling interests, net	(108)						(108)	(120)				(120)
Contribution from member								662		662
Purchase of Universal Studios Japan noncontrolling interests	(2,238)		(696)			194	(1,736)	(2,299)		(704)	141	(1,736)
Other	312		51				261	650		184		466
Net income	22,849			22,735			114	5,186		5,080		106
Ending Balance at Dec. 31, 2017	69,459		37,497	38,202	(7,517)	379	843						55	0
Ending Balance at Dec. 31, 2017								43,041		42,148	(20)	913
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions from (distributions to) noncontrolling interests, net		(39)							(65)
Other		(123)							(84)
Net income		73							28
Ending Balance at Dec. 31, 2017	1,357	1,357						409	409
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effects of adoption of accounting standards	33			(43)		76		0		(232)	232
Stock compensation plans	607		607
Repurchases of common stock under repurchase program and employee plans	(5,329)		(920)	(4,408)									(1)
Employee stock purchase plans	214		214
Dividends declared / Distributions to member	(3,499)			(3,499)				(1,627)		(1,627)
Other comprehensive income (loss)	(864)					(823)	(41)	1			42	(41)
Contributions from (distributions to) noncontrolling interests, net	294						294	299				299
Other	(217)		63				(280)	(202)		92		(294)
Net income	11,804			11,731			73	5,269		5,237		32
Ending Balance at Dec. 31, 2018	72,502		$ 37,461	$ 41,983	$ (7,517)	$ (368)	$ 889						$ 54	$ 0
Ending Balance at Dec. 31, 2018								46,781		$ 45,618	$ 254	$ 909
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions from (distributions to) noncontrolling interests, net		(56)							(52)
Other		(43)							(4)
Net income		58							36
Ending Balance at Dec. 31, 2018	$ 1,316	$ 1,316						$ 389	$ 389

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Business And Basis Of Presentation [Line Items]
Basis of Presentation and Summary of Significant Accounting Policies	Note 1: Basis of Presentation and Summary of Significant Accounting Policies We are a global media and technology company with three primary businesses, Comcast Cable, NBCUniversal and Sky. We were incorporated under the laws of Pennsylvania in December 2001. Through our predecessors, we have developed, managed and operated cable systems since 1963. In the fourth quarter of 2018, we acquired a 100% interest in Sky through a series of transactions, for total cash consideration of £30.2 billion (approximately $39.4 billion using the exchange rates on the purchase dates). We present our operations for (1) Comcast Cable in one reportable business segment, referred to as Cable Communications; (2) NBCUniversal in four reportable business segments: Cable Networks, Broadcast Television, Filmed Entertainment and Theme Parks (collectively, the “NBCUniversal segments”); and (3) Sky in one reportable business segment. See Note 2 for additional information on our reportable business segments. Basis of Presentation The accompanying consolidated financial statements include all entities in which we have a controlling voting interest and variable interest entities (“VIEs”) required to be consolidated in accordance with generally accepted accounting principles in the United States (“GAAP”). We translate assets and liabilities of our foreign operations where the functional currency is the local currency, primarily the British pound, euro, Japanese yen and Chinese renminbi, into U.S. dollars at the exchange rate as of the balance sheet date and translate revenue and expenses using average monthly exchange rates. The related translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in our consolidated balance sheet. Any foreign currency transaction gains or losses are included in our consolidated statement of income. Reclassifications Reclassifications have been made to our consolidated financial statements for the prior periods to conform to classifications used in 2018 . See Note 9 for a discussion of the effects of the adoption of new accounting pronouncements on our consolidated financial statements. Accounting Policies Our consolidated financial statements are prepared in accordance with GAAP, which require us to select accounting policies, including in certain cases industry-specific policies, and make estimates that affect the reported amount of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and contingent liabilities. Actual results could differ from these estimates. We believe that the judgments and related estimates for the following items are critical in the preparation of our consolidated financial statements: • valuation and impairment testing of cable franchise rights (see Note 12) • film and television costs (see Note 4) • fair value of acquisition-related assets and liabilities (see Note 8) In addition, the following accounting policies are specific to the industries in which we operate: • capitalization and amortization of film and television costs (see Note 4) • costs for connecting customers to our cable systems (see Note 11) Information on other accounting policies and methods that we use in the preparation of our consolidated financial statements are included, where applicable, in their respective footnotes that follow. Below is a discussion of accounting policies and methods used in our consolidated financial statements that are not presented within other footnotes. Advertising Expenses Advertising costs are expensed as incurred. Cash Equivalents The carrying amounts of our cash equivalents approximate their fair values. Our cash equivalents consist primarily of money market funds and U.S. government obligations, as well as commercial paper and certificates of deposit with maturities of three months or less when purchased. Derivative Financial Instruments We use derivative financial instruments to manage our exposure to the risks associated with fluctuations in interest rates, foreign exchange rates and equity prices. Our objective is to manage the financial and operational exposure arising from these risks by offsetting gains and losses on the underlying exposures with gains and losses on the derivatives used to economically hedge them. Our derivative financial instruments are recorded in our consolidated balance sheet at fair value. Refer to Note 7 for further information on foreign exchange derivatives related to debt. The impact of our remaining derivative financial instruments on our consolidated financial statements was not material in any of the periods presented. Fair Value Measurements The accounting guidance related to fair value measurements establishes a hierarchy based on the types of inputs used for the various valuation techniques (market approach, income approach and cost approach). The levels of the hierarchy are described below. • Level 1: Values are determined using quoted market prices for identical financial instruments in an active market • Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable • Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation We use these levels of hierarchy to measure the fair value of certain financial instruments on a recurring basis, such as for investments; on a non-recurring basis, such as for acquisitions and impairment testing; for disclosure purposes, such as for long-term debt; and for other applications, as discussed in their respective footnotes. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation and classification within the fair value hierarchy. Asset Retirement Obligations Certain of our cable franchise agreements and lease agreements contain provisions requiring us to restore facilities or remove property in the event that the franchise or lease agreement is not renewed. We expect to continually renew our cable franchise agreements and therefore cannot reasonably estimate liabilities associated with such agreements. A remote possibility exists that franchise agreements could be terminated unexpectedly, which could result in us incurring significant expense in complying with restoration or removal provisions. We do not have any material liabilities related to asset retirements recorded in our consolidated financial statements.
NBCUniversal Media LLC [Member]
Business And Basis Of Presentation [Line Items]
Basis of Presentation and Summary of Significant Accounting Policies	Note 1: Basis of Presentation and Summary of Significant Accounting Policies Unless indicated otherwise, throughout these notes to the consolidated financial statements, we refer to NBCUniversal and its consolidated subsidiaries as “we,” “us” and “our.” We are one of the world’s leading media and entertainment companies that develops, produces and distributes entertainment, news and information, sports, and other content for global audiences, and owns and operates theme parks worldwide. We present our operations as the following four reportable business segments: Cable Networks, Broadcast Television, Filmed Entertainment and Theme Parks. See Note 2 for additional information on our reportable business segments. Basis of Presentation The accompanying consolidated financial statements include all entities in which we have a controlling voting interest and variable interest entities (“VIEs”) required to be consolidated in accordance with generally accepted accounting principles in the United States (“GAAP”). Transactions between NBCUniversal and both Comcast and Comcast’s consolidated subsidiaries are reflected in these consolidated financial statements and disclosed as related party transactions when material. We translate assets and liabilities of our foreign operations where the functional currency is the local currency, primarily the Japanese yen, euro, British pound and Chinese renminbi, into U.S. dollars at the exchange rate as of the balance sheet date and translate revenue and expenses using average monthly exchange rates. The related translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in our consolidated balance sheet. Any foreign currency transaction gains or losses are included in our consolidated statement of income. Accounting Policies Our consolidated financial statements are prepared in accordance with GAAP, which require us to select accounting policies, including in certain cases industry-specific policies, and make estimates that affect the reported amount of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and contingent liabilities. Actual results could differ from these estimates. We believe that the judgments and related estimates for the following items are critical in the preparation of our consolidated financial statements: • film and television costs (see Note 4) • goodwill and intangible assets (see Note 11) In addition, the following accounting policy is specific to the industries in which we operate: • capitalization and amortization of film and television costs (see Note 4) Information on other accounting policies and methods that we use in the preparation of our consolidated financial statements are included, where applicable, in their respective footnotes that follow. Below is a discussion of accounting policies and methods used in our consolidated financial statements that are not presented within other footnotes. Advertising Expenses Advertising costs are expensed as incurred. Cash Equivalents The carrying amounts of our cash equivalents approximate their fair values. Our cash equivalents consist primarily of money market funds and U.S. government obligations, as well as commercial paper and certificates of deposit with maturities of three months or less when purchased. Derivative Financial Instruments We use derivative financial instruments to manage our exposure to the risks associated with fluctuations in foreign exchange rates and interest rates. Our objective is to manage the financial and operational exposure arising from these risks by offsetting gains and losses on the underlying exposures with gains and losses on the derivatives used to economically hedge them. Our derivative financial instruments are recorded in our consolidated balance sheet at fair value. The impact of our derivative financial instruments on our consolidated financial statements was not material in any of the periods presented. Fair Value Measurements The accounting guidance related to fair value measurements establishes a hierarchy based on the types of inputs used for the various valuation techniques (market approach, income approach and cost approach). The levels of the hierarchy are described below. • Level 1: Values are determined using quoted market prices for identical financial instruments in an active market • Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable • Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation We use these levels of hierarchy to measure the fair value of certain financial instruments on a recurring basis, such as for investments; on a non-recurring basis, such as for acquisitions and impairment testing; for disclosure purposes, such as long-term debt; and for other applications, as discussed in their respective footnotes. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation and classification within the fair value hierarchy.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting Information [Line Items]
Segment Information	Note 2: Segment Information Our Cable Communications segment primarily manages and operates cable systems that serve residential and business customers in the United States and sells advertising. As of December 31, 2018, our cable systems had 30.3 million total customer relationships, including 28.0 million residential and 2.3 million business customer relationships, of which 27.2 million received our high-speed internet service, 22.0 million received our video service, 11.4 million received our voice service and 1.3 million received our security and automation service. Our Cable Networks segment consists primarily of a diversified portfolio of cable television networks. Our Cable Networks segment is comprised of our national cable networks that provide a variety of entertainment, news and information, and sports content; our regional sports and news networks; our international cable networks; our cable television studio production operations; and our various digital properties. Our Broadcast Television segment consists primarily of the NBC and Telemundo broadcast networks, our NBC and Telemundo owned local broadcast television stations, the NBC Universo national cable network, our broadcast television studio production operations, and our various digital properties. Our Filmed Entertainment segment primarily produces, acquires, markets and distributes filmed entertainment worldwide. Our films are produced primarily under the Universal Pictures, Illumination, DreamWorks Animation and Focus Features names. Our Theme Parks segment consists primarily of our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. In addition, along with a consortium of Chinese state-owned companies, we are developing a Universal theme park and resort in Beijing, China. Our Sky segment consists of the operations of Sky, which is a leading entertainment company in Europe. It is primarily a direct-to-consumer business, providing satellite and OTT video, high-speed internet, voice, and wireless phone services, and as of December 31, 2018 Sky had 23.6 million retail customer relationships. Sky is also a content business, operating entertainment networks, the Sky News broadcast network and Sky Sports networks. Our other business interests , which are included in Corporate and Other, consist primarily of our wireless phone service and Comcast Spectacor, which owns the Philadelphia Flyers and the Wells Fargo Center arena in Philadelphia, Pennsylvania. We use Adjusted EBITDA to evaluate the profitability of our operating segments, and the components of net income attributable to Comcast Corporation excluded from Adjusted EBITDA are not separately evaluated. To be consistent with our current management reporting presentation, certain 2018, 2017 and 2016 operating results were reclassified related to certain NBCUniversal businesses now presented in the Sky segment. We do not present a measure of total assets for our reportable business segments as this information is not used by management to allocate resources and capital. Our financial data by business segment is presented in the tables below. (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2018 Cable Communications $ 55,143 $ 22,447 $ 8,264 $ 7,716 $ 1,282 NBCUniversal Cable Networks (a) 11,773 4,428 738 42 23 Broadcast Television (a) 11,439 1,657 146 204 81 Filmed Entertainment 7,152 734 145 35 25 Theme Parks 5,683 2,455 660 1,143 173 Headquarters and Other (b) 63 (680 ) 419 306 146 Eliminations (a)(c) (349 ) 4 — — — NBCUniversal 35,761 8,598 2,108 1,730 448 Sky 4,587 692 539 222 137 Corporate and Other (d) 1,403 (1,545 ) 106 106 68 Eliminations (a)(c) (2,387 ) (27 ) — — — Comcast Consolidated $ 94,507 $ 30,165 $ 11,017 $ 9,774 $ 1,935 (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2017 Cable Communications $ 53,070 $ 21,068 $ 8,006 $ 7,952 $ 1,241 NBCUniversal Cable Networks 10,497 4,053 755 33 19 Broadcast Television 9,563 1,251 133 180 22 Filmed Entertainment 7,595 1,276 109 58 23 Theme Parks 5,443 2,384 648 960 78 Headquarters and Other (b) 45 (741 ) 396 271 153 Eliminations (c) (307 ) (5 ) — — — NBCUniversal 32,836 8,218 2,041 1,502 295 Corporate and Other (d) 1,193 (1,372 ) 83 96 69 Eliminations (c) (2,070 ) 42 — — — Comcast Consolidated $ 85,029 $ 27,956 $ 10,130 $ 9,550 $ 1,605 (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2016 Cable Communications $ 50,577 $ 20,014 $ 7,538 $ 7,596 $ 1,243 NBCUniversal Cable Networks (a) 10,324 3,681 745 32 20 Broadcast Television (a) 10,085 1,293 125 153 19 Filmed Entertainment 6,229 662 47 33 16 Theme Parks 4,946 2,190 512 922 72 Headquarters and Other (b) 20 (699 ) 376 312 156 Eliminations (a)(c) (328 ) 11 — — — NBCUniversal 31,276 7,138 1,805 1,452 283 Corporate and Other (d) 886 (849 ) 83 87 26 Eliminations (a)(c) (2,003 ) (46 ) — — — Comcast Consolidated $ 80,736 $ 26,257 $ 9,426 $ 9,135 $ 1,552 (a) The revenue and operating costs and expenses associated with our broadcast of the 2018 PyeongChang Olympics and the 2016 Rio Olympics were reported in our Cable Networks and Broadcast Television segments. The revenue and operating costs and expenses associated with our broadcast of the 2018 Super Bowl were reported in our Broadcast Television segment. Included in Eliminations are transactions relating to these events that our Broadcast Television and Cable Networks segments enter into with our other segments. (b) NBCUniversal Headquarters and Other activities include costs associated with overhead, allocations, personnel and headquarter initiatives. (c) Included in Eliminations are transactions that our segments enter into with one another. The most common types of transactions are the following: • our Cable Networks segment generates revenue by selling programming to our Cable Communications segment, which represents a substantial majority of the revenue elimination amount • our Broadcast Television segment generates revenue from the fees received under retransmission consent agreements with our Cable Communications segment • our Cable Communications segment generates revenue by selling advertising and by selling the use of satellite feeds to our Cable Networks segment • our Cable Networks and Broadcast Television segments generate revenue by selling advertising to our Cable Communications segment • our Filmed Entertainment and Broadcast Television segments generate revenue by licensing content to our Cable Networks segment; for segment reporting, this revenue is recognized as the programming rights asset for the licensed content is amortized based on third-party revenue • our Filmed Entertainment, Cable Networks and Broadcast Television segments generate revenue by licensing content to our Sky segment (d) Corporate and Other activities include costs associated with overhead and personnel, revenue and expenses associated with other business development initiatives, including our wireless phone service, and the operations of Comcast Spectacor, which owns the Philadelphia Flyers and the Wells Fargo Center arena in Philadelphia, Pennsylvania. (e) We use Adjusted EBITDA as the measure of profit or loss for our operating segments. Adjusted EBITDA is defined as net income attributable to Comcast Corporation before net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock, income tax benefit (expense), investment and other income (loss), net, interest expense, depreciation and amortization expense, and other operating gains and losses (such as impairment charges related to fixed and intangible assets and gains or losses on the sale of long-lived assets), if any. From time to time we may exclude from Adjusted EBITDA the impact of certain events, gains, losses or other charges (such as significant legal settlements) that affect the period-to-period comparability of our operating performance. Our reconciliation of the aggregate amount of Adjusted EBITDA for our reportable segments to consolidated income before income taxes is presented in the table below. Year ended December 31 (in millions) 2018 2017 2016 Adjusted EBITDA $ 30,165 $ 27,956 $ 26,257 Adjustment for legal settlement (125 ) (250 ) — Adjustment for Sky transaction-related costs (355 ) — — Depreciation (8,281 ) (7,914 ) (7,464 ) Amortization (2,736 ) (2,216 ) (1,962 ) Other operating gains 341 442 — Interest expense (3,542 ) (3,086 ) (2,942 ) Investment and other income (loss), net (225 ) 421 437 Income before income taxes $ 15,242 $ 15,353 $ 14,326
NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Segment Information	Note 2: Segment Information Our Cable Networks segment consists primarily of a diversified portfolio of cable television networks. Our Cable Networks segment is comprised of our national cable networks that provide a variety of entertainment, news and information, and sports content; our regional sports and news networks; our international cable networks; our cable television studio production operations; and our various digital properties. Our Broadcast Television segment consists primarily of the NBC and Telemundo broadcast networks, our NBC and Telemundo owned local broadcast television stations, the NBC Universo national cable network, our broadcast television studio production operations, and our various digital properties. Our Filmed Entertainment segment primarily produces, acquires, markets and distributes filmed entertainment worldwide. Our films are produced primarily under the Universal Pictures, Illumination, DreamWorks Animation and Focus Features names. Our Theme Parks segment consists primarily of our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. In addition, along with a consortium of Chinese state-owned companies, we are developing a Universal theme park and resort in Beijing, China. We use Adjusted EBITDA to evaluate the profitability of our operating segments, and the components of net income attributable to NBCUniversal excluded from Adjusted EBITDA are not separately evaluated. To be consistent with our current management reporting presentation, certain 2018, 2017 and 2016 operating results were reclassified related to certain NBCUniversal businesses now presented in Headquarters and Other. We do not present a measure of total assets for our reportable business segments as this information is not used by management to allocate resources and capital. Our financial data by business segment is presented in the tables below. (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2018 Cable Networks (a) $ 11,773 $ 4,428 $ 738 $ 42 $ 23 Broadcast Television (a) 11,439 1,657 146 204 81 Filmed Entertainment 7,152 734 145 35 25 Theme Parks 5,683 2,455 660 1,143 173 Headquarters and Other (b) 212 (645 ) 419 306 146 Eliminations (a)(c) (364 ) 4 — — — Total $ 35,895 $ 8,633 $ 2,108 $ 1,730 $ 448 (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2017 Cable Networks $ 10,497 $ 4,053 $ 755 $ 33 $ 19 Broadcast Television 9,563 1,251 133 180 22 Filmed Entertainment 7,595 1,276 109 58 23 Theme Parks 5,443 2,384 648 960 78 Headquarters and Other (b) 179 (779 ) 396 271 153 Eliminations (c) (327 ) (4 ) — — — Total $ 32,950 $ 8,181 $ 2,041 $ 1,502 $ 295 (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2016 Cable Networks (a) $ 10,324 $ 3,681 $ 745 $ 32 $ 20 Broadcast Television (a) 10,085 1,293 125 153 19 Filmed Entertainment 6,229 662 47 33 16 Theme Parks 4,946 2,190 512 922 72 Headquarters and Other (b) 157 (674 ) 376 312 156 Eliminations (a)(c) (343 ) 11 — — — Total $ 31,398 $ 7,163 $ 1,805 $ 1,452 $ 283 (a) The revenue and operating costs and expenses associated with our broadcast of the 2018 PyeongChang Olympics and the 2016 Rio Olympics were reported in our Cable Networks and Broadcast Television segments. The revenue and operating costs and expenses associated with our broadcast of the 2018 Super Bowl were reported in our Broadcast Television segment. Included in Eliminations are transactions relating to these events that our Broadcast Television and Cable Networks segments enter into with our other segments. (b) Headquarters and Other activities include costs associated with overhead, allocations, personnel and headquarter initiatives. (c) Eliminations are transactions that our segments enter into with one another, which consisted primarily of the licensing of film and television content from our Filmed Entertainment and Broadcast Television segments to our Cable Networks segment; for segment reporting, revenue is recognized as the programming rights asset for the licensed content is amortized based on third-party revenue. (d) We use Adjusted EBITDA as the measure of profit or loss for our operating segments. Adjusted EBITDA is defined as net income attributable to NBCUniversal before net (income) loss attributable to noncontrolling interests, income tax expense, investment and other income (loss), net, interest expense, depreciation and amortization expense, and other operating gains and losses (such as impairment charges related to fixed and intangible assets and gains or losses on the sale of long-lived assets), if any. From time to time we may exclude from Adjusted EBITDA the impact of certain events, gains, losses or other charges (such as significant legal settlements) that affect the period-to-period comparability of our operating performance. Our reconciliation of the aggregate amount of Adjusted EBITDA for our reportable segments to consolidated income before income taxes is presented in the table below. Year ended December 31 (in millions) 2018 2017 2016 Adjusted EBITDA $ 8,633 $ 8,181 $ 7,163 Depreciation (1,001 ) (994 ) (861 ) Amortization (1,107 ) (1,047 ) (944 ) Other operating gains 141 337 — Interest expense (489 ) (727 ) (595 ) Investment and other income (loss), net (521 ) (144 ) 24 Income before income taxes $ 5,656 $ 5,606 $ 4,787

Revenue

Revenue - Accounting Standards Update 2014-09 [Member]	12 Months Ended
	Dec. 31, 2018
Revenue [Line Items]
Revenue	Note 3: Revenue Year ended December 31 (in millions) 2018 2017 2016 Residential: High-speed internet $ 17,144 $ 15,681 $ 14,421 Video 22,455 22,874 22,204 Voice 3,960 4,090 4,159 Business services 7,129 6,437 5,705 Advertising 2,795 2,450 2,626 Other 1,660 1,538 1,462 Total Cable Communications (a) 55,143 53,070 50,577 Distribution 6,826 6,081 5,978 Advertising 3,587 3,359 3,530 Content licensing and other 1,360 1,057 816 Total Cable Networks 11,773 10,497 10,324 Advertising 7,010 5,654 6,834 Content licensing 2,182 2,114 1,837 Distribution and other 2,247 1,795 1,414 Total Broadcast Television 11,439 9,563 10,085 Theatrical 2,111 2,192 1,560 Content licensing 2,899 2,956 2,518 Home entertainment 1,048 1,287 1,182 Other 1,094 1,160 969 Total Filmed Entertainment 7,152 7,595 6,229 Total Theme Parks 5,683 5,443 4,946 Headquarters and Other 63 45 20 Eliminations (b) (349 ) (307 ) (328 ) Total NBCUniversal 35,761 32,836 31,276 Direct-to-consumer 3,632 — — Content 304 — — Advertising 651 — — Total Sky 4,587 — — Corporate and Other 1,403 1,193 886 Eliminations (b) (2,387 ) (2,070 ) (2,003 ) Total revenue $ 94,507 $ 85,029 $ 80,736 (a) For 2018, 2017 and 2016, 2.7% , 2.8% and 2.9% , respectively, of Cable Communications segment revenue was derived from franchise and other regulatory fees. (b) Included in Eliminations are transactions that our segments enter into with one another. See Note 2 for a description of these transactions. We operate primarily in the United States, but also in select international markets primarily in Europe and Asia. The table below summarizes revenue by geographic location. Year ended December 31 (in millions) 2018 2017 2016 United States $ 82,233 $ 77,246 $ 74,212 Foreign 12,274 7,783 6,524 Total revenue $ 94,507 $ 85,029 $ 80,736 No single customer accounted for a significant amount of revenue in any period presented. Cable Communications Segment Residential Our Cable Communications segment generates revenue from residential customers that subscribe to our high-speed internet, video, voice, and security and automation services, which we market individually and as bundled services at a discounted rate in the United States. Revenue from residential customers that purchase bundled services at a discounted rate is allocated between the separate services based on the respective stand-alone selling prices. The stand-alone selling prices are determined based on the current prices at which we separately sell the cable services. Significant judgment is used to determine performance obligations that should be accounted for separately and the allocation of revenue when services are combined in a bundle. Revenue related to our security and automation services is reported in other revenue. We recognize revenue from residential cable services as the services are provided on a monthly basis. Subscription rates and related charges vary according to the services and features customers receive. Customers are typically billed in advance and pay on a monthly basis. Installation fees are deferred and recognized as revenue over the period of benefit to the customer, which is less than a year for residential customers. While a portion of our residential customers are subject to contracts for their cable services, which are typically 2 years in length, based on our evaluation of the terms of these contracts, we recognize revenue for these cable services on a basis that is consistent with our customers that are not subject to contracts. Our cable services generally involve customer premise equipment, such as set-top boxes, cable modems and wireless gateways. The timing and pattern of recognition for customer premise equipment revenue are consistent with those of our residential cable services. Sales commissions related to our residential customers are expensed as incurred, as the related period of benefit is less than a year. Under the terms of our cable franchise agreements, we are generally required to pay the cable franchising authority an amount based on our gross video revenue. We generally pass these and other similar fees through to our cable services customers and classify these fees in the respective cable service revenue, with the corresponding costs included in other operating and administrative expenses. Business Services Our Cable Communications segment generates revenue from business customers that subscribe to a variety of products and services. Our small business services offerings primarily include high-speed internet services, as well as voice and video services, similar to those that we provide to our residential customers, and also include cloud-based solutions that provide file sharing, online backup and web conferencing, among other features. We also offer Ethernet network services that connect multiple locations and provide higher downstream and upstream speed options to medium-sized customers and larger enterprises, as well as advanced voice services. In addition, we provide cellular backhaul services to mobile network operators to help these customers manage their network bandwidth. Recently, we have expanded our enterprise service offerings to include a software-defined networking product and our managed solutions business to offer enterprise customers support related to Wi-Fi networks, router management, network security, business continuity risks and other services. We primarily offer our enterprise service offerings to Fortune 1000 companies and other large enterprises with multiple locations both within and outside of our cable distribution footprint where we have agreements with other companies to use their networks to provide coverage. We recognize revenue from business services as the services are provided on a monthly basis. Substantially all of our business customers are initially under contracts, with terms typically ranging from 2 years for small and medium-sized businesses to up to 5 years for larger enterprises. At any given time, the amount of future revenue to be earned related to fixed pricing under existing agreements is equal to approximately half of our annual business services revenue, of which the substantial majority will be recognized within 2 years . Customers with contracts may only discontinue service in accordance with the terms of their contracts. We receive payments from business customers based on a billing schedule established in our contracts, which is typically on a monthly basis. Installation revenue related to our business services customers and sales commissions are generally deferred and recognized over the respective contract terms. Advertising Our Cable Communications segment generates revenue from the sale of advertising and technology, tools and solutions relating to advertising businesses. As part of our distribution agreements with cable networks, we generally receive an allocation of scheduled advertising time that we sell to local, regional and national advertisers. In most cases, the available advertising units are sold by our sales force. We also represent the advertising sales efforts of other multichannel video providers in some markets. Since we are acting as the principal in these arrangements, we record the advertising that is sold in advertising revenue and the fees paid to multichannel video providers in other operating and administrative expenses. In some cases, we work with representation firms as an extension of our sales force to sell a portion of the advertising units allocated to us and record the revenue net of agency commissions. In addition, we generate revenue from the sale of advertising on digital platforms. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms and conditions are agreed upon. Advertising revenue from these arrangements is recognized in the period in which advertisements are aired or viewed. Payment terms vary by contract, although terms generally require payment within 30 to 60 days from when advertisements are aired or viewed. In addition, our advertising business also provides technology, tools, data-driven services and marketplace solutions to customers in the media industry, which allows advertisers to more effectively engage with their target audiences. Revenue earned in this manner is recognized when services are provided. NBCUniversal Segments Distribution Our Cable Networks segment generates distribution revenue from the distribution of our cable network programming to traditional and virtual multichannel video providers. Our Broadcast Television segment generates distribution revenue from the fees received under retransmission consent agreements and associated fees received from NBC-affiliated local broadcast television stations. Distribution revenue is accounted for as a license of functional intellectual property and is recognized as programming is provided on a monthly basis, generally under multiyear agreements. Monthly fees received under distribution agreements with multichannel video providers are generally based on the number of subscribers. Payment terms and conditions vary by contract type, although terms generally include payment within 30 to 60 days. Advertising Our Cable Networks and Broadcast Television segments generate advertising revenue from the sale of advertising on our cable and broadcast networks, our owned local broadcast television stations and various digital properties. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms are agreed upon. Advertising revenue is recognized, net of agency commissions, in the period in which advertisements are aired or viewed and payment occurs thereafter, with payment generally required within 30 days. In some instances, we guarantee audience ratings for the advertisements. To the extent there is a shortfall in contracts where the ratings were guaranteed, a portion of the revenue is deferred until the shortfall is settled, typically by providing additional advertising units generally within one year of the original airing. Theatrical Our Filmed Entertainment segment generates theatrical revenue from the worldwide theatrical release of our produced and acquired films for exhibition in movie theaters. Theatrical revenue is affected by the timing, nature and number of films released in movie theaters and their acceptance by audiences. It is also affected by the number of exhibition screens, ticket prices, the percentage of ticket sale retention by the exhibitors and the popularity of competing films at the time our films are released. We recognize theatrical revenue as the films are viewed and exhibited in theaters and payment generally occurs within 30 days after exhibition. Content Licensing Our Cable Networks, Broadcast Television and Filmed Entertainment segments generate revenue from the licensing of our owned film and television content in the United States and internationally to cable, broadcast and premium networks and subscription video on demand services. Our content licensing agreements generally include fixed pricing and span multiple years. For example, following a film’s theatrical release, our Filmed Entertainment segment may license the exhibition rights of a film to different customers over multiple successive distribution windows. We recognize revenue when the content is delivered and available for use by the licensee. When the term of an existing agreement is renewed or extended, we recognize revenue at the later of when the content is available or when the renewal or extension period begins. Payment terms and conditions vary by contract type, although payments are generally collected over the license term. The amount of future revenue to be earned related to fixed pricing under existing agreements primarily relates to our Filmed Entertainment segment, which at any given time equals approximately 1 to 2 years of our annual Filmed Entertainment content licensing revenue. The majority of this revenue will be recognized within 2 years. This amount may fluctuate from period to period depending on the timing of the releases and the availability of content under existing agreements and may not represent the total content licensing revenue expected to be recognized as it does not include revenue from future agreements or from variable pricing or optional purchases under existing agreements. For our content licensing agreements that include variable pricing, such as pricing based on the number of subscribers to a subscription video on demand service sold by our customers, we generally recognize revenue as our customers sell to their subscribers. Home Entertainment Our Filmed Entertainment segment generates revenue from the sale of our produced and acquired films on standard-definition digital video discs and Blu-ray discs (together, “DVDs”) and through digital distribution services. Our Cable Networks and Broadcast Television networks also generate revenue from the sale of owned programming on DVDs and through digital distribution services, which is reported in other revenue. We generally recognize revenue from DVD sales, net of estimated returns and customer incentives, on the date that DVDs are delivered to and made available for sale by retailers. Payment terms generally include payment within 60 to 90 days from delivery to the retailer. Theme Parks Our Theme Parks segment generates revenue primarily from ticket sales and guest spending at our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. Guest spending includes in-park spending on food, beverages and merchandise. We recognize revenue from theme park ticket sales when the tickets are used, generally within a year from the date of purchase. For annual passes, we generally recognize revenue on a straight-line basis over the period the pass is available to be used. We recognize revenue from guest spending at the point of sale. Sky Segment Direct-to-Consumer The majority of Sky’s revenue is direct-to-consumer, which primarily includes subscription revenue relating to the sale of video services to residential and business customers. Sky also provides high-speed internet, voice and wireless phone services in select countries. Generally, all of our residential customers are initially under contracts, with terms typically ranging from rolling monthly to 2 years , depending on the product and territory, and may only discontinue service in accordance with the terms of their contracts. Subscription rates and related charges vary according to the services and features customers receive and the types of equipment they use. Sky’s video, high-speed internet, voice and wireless phone services generally may be sold individually or in bundles. We recognize revenue from video, high-speed internet, voice and wireless phone services as the services are provided on a monthly basis. At any given time, the amount of future revenue to be earned related to existing agreements is equal to less than half of our annual subscription revenue, which generally will be recognized within 2 years . Content Sky’s content revenue includes revenue from the distribution of its channels on third-party platforms and the licensing of owned programming to third-party video providers. Refer to the NBCUniversal segment discussion of distribution and content licensing revenue for accounting policies for these types of arrangements. Advertising Sky sells advertising and sponsorships across its owned channels and where it represents the sales efforts of third-party channels. Sky also sells targeted advertising in the U.K., Ireland and Italy, and generates revenue from online and mobile advertising and advertising across its On Demand services. Advertising revenue is recognized when the advertising is aired or viewed. Since Sky is acting as the principal in the arrangements where it represents the sales efforts of third parties, we record the advertising that is sold in advertising revenue and the fees paid to the third-party channels in other operating and administrative expenses. Consolidated Balance Sheet The following tables summarize our accounts receivable and other balances that are not separately presented in our consolidated balance sheet that relate to the recognition of revenue and collection of the related cash , as well as deferred costs associated with our contracts with customers. December 31 (in millions) 2018 2017 Receivables, gross $ 11,456 $ 9,122 Less: Allowance for doubtful accounts 352 288 Receivables, net $ 11,104 $ 8,834 December 31 (in millions) 2018 2017 Noncurrent receivables (included in other noncurrent assets, net) $ 1,399 $ 1,184 Contract acquisition and fulfillment costs (included in other noncurrent assets, net) $ 991 $ 922 Noncurrent deferred revenue (included in other noncurrent liabilities) $ 650 $ 497 In our Cable Communications and Sky segments, we manage credit risk by screening applicants through the use of internal customer information, identification verification tools and credit bureau data, as well as by offering customers the opportunity to establish automatic monthly payments. If a customer’s account is delinquent, various measures are used to collect outstanding amounts, including termination of the customer’s cable services.
NBCUniversal Media LLC [Member]
Revenue [Line Items]
Revenue	Note 3: Revenue Year ended December 31 (in millions) 2018 2017 2016 Distribution $ 6,826 $ 6,081 $ 5,978 Advertising 3,587 3,359 3,530 Content licensing and other 1,360 1,057 816 Total Cable Networks 11,773 10,497 10,324 Advertising 7,010 5,654 6,834 Content licensing 2,182 2,114 1,837 Distribution and other 2,247 1,795 1,414 Total Broadcast Television 11,439 9,563 10,085 Theatrical 2,111 2,192 1,560 Content licensing 2,899 2,956 2,518 Home entertainment 1,048 1,287 1,182 Other 1,094 1,160 969 Total Filmed Entertainment 7,152 7,595 6,229 Total Theme Parks 5,683 5,443 4,946 Headquarters and Other 212 179 157 Eliminations (a) (364 ) (327 ) (343 ) Total NBCUniversal $ 35,895 $ 32,950 $ 31,398 (a) Included in Eliminations are transactions that our segments enter into with one another. See Note 2 for a description of these transactions. We operate primarily in the United States, but also in select international markets primarily in Europe and Asia. The table below summarizes revenue by geographic location. Year ended December 31 (in millions) 2018 2017 2016 United States $ 28,309 $ 25,303 $ 24,907 Foreign 7,586 7,647 6,491 Total revenue $ 35,895 $ 32,950 $ 31,398 Distribution Our Cable Networks segment generates distribution revenue from the distribution of our cable network programming to traditional and virtual multichannel video providers. Our Broadcast Television segment generates distribution revenue from the fees received under retransmission consent agreements and associated fees received from NBC-affiliated local broadcast television stations. Distribution revenue is accounted for as a license of functional intellectual property and is recognized as programming is provided on a monthly basis, generally under multiyear agreements. Monthly fees received under distribution agreements with multichannel video providers are generally based on the number of subscribers. Payment terms and conditions vary by contract type, although terms generally include payment within 30 to 60 days. Advertising Our Cable Networks and Broadcast Television segments generate advertising revenue from the sale of advertising on our cable and broadcast networks, our owned local broadcast television stations and various digital properties. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms are agreed upon. Advertising revenue is recognized, net of agency commissions, in the period in which advertisements are aired or viewed and payment occurs thereafter, with payment generally required within 30 days. In some instances, we guarantee audience ratings for the advertisements. To the extent there is a shortfall in contracts where the ratings were guaranteed, a portion of the revenue is deferred until the shortfall is settled, typically by providing additional advertising units generally within one year of the original airing. Theatrical Our Filmed Entertainment segment generates theatrical revenue from the worldwide theatrical release of our produced and acquired films for exhibition in movie theaters. Theatrical revenue is affected by the timing, nature and number of films released in movie theaters and their acceptance by audiences. It is also affected by the number of exhibition screens, ticket prices, the percentage of ticket sale retention by the exhibitors and the popularity of competing films at the time our films are released. We recognize theatrical revenue as the films are viewed and exhibited in theaters and payment generally occurs within 30 days after exhibition. Content Licensing Our Cable Networks, Broadcast Television and Filmed Entertainment segments generate revenue from the licensing of our owned film and television content in the United States and internationally to cable, broadcast and premium networks and subscription video on demand services. Our content licensing agreements generally include fixed pricing and span multiple years. For example, following a film’s theatrical release, our Filmed Entertainment segment may license the exhibition rights of a film to different customers over multiple successive distribution windows. We recognize revenue when the content is delivered and available for use by the licensee. When the term of an existing agreement is renewed or extended, we recognize revenue at the later of when the content is available or when the renewal or extension period begins. Payment terms and conditions vary by contract type, although payments are generally collected over the license term. The amount of future revenue to be earned related to fixed pricing under existing agreements primarily relates to our Filmed Entertainment segment, which at any given time equals approximately 1 to 2 years of our annual Filmed Entertainment content licensing revenue. The majority of this revenue will be recognized within 2 years. This amount may fluctuate from period to period depending on the timing of the releases and the availability of content under existing agreements and may not represent the total content licensing revenue expected to be recognized as it does not include revenue from future agreements or from variable pricing or optional purchases under existing agreements. For our content licensing agreements that include variable pricing, such as pricing based on the number of subscribers to a subscription video on demand service sold by our customers, we generally recognize revenue as our customers sell to their subscribers. Home Entertainment Our Filmed Entertainment segment generates revenue from the sale of our produced and acquired films on standard-definition digital video discs and Blu-ray discs (together, “DVDs”) and through digital distribution services. Our Cable Networks and Broadcast Television networks also generate revenue from the sale of owned programming on DVDs and through digital distribution services, which is reported in other revenue. We generally recognize revenue from DVD sales, net of estimated returns and customer incentives, on the date that DVDs are delivered to and made available for sale by retailers. Payment terms generally include payment within 60 to 90 days from delivery to the retailer. Theme Parks Our Theme Parks segment generates revenue primarily from ticket sales and guest spending at our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. Guest spending includes in-park spending on food, beverages and merchandise. We recognize revenue from theme park ticket sales when the tickets are used, generally within a year from the date of purchase. For annual passes, we generally recognize revenue on a straight-line basis over the period the pass is available to be used. We recognize revenue from guest spending at the point of sale. Consolidated Balance Sheet The following tables summarize our accounts receivable and other balances that are not separately presented in our consolidated balance sheet that relate to the recognition of revenue and collection of the related cash . December 31 (in millions) 2018 2017 Receivables, gross $ 7,392 $ 7,055 Less: Allowance for doubtful accounts 99 88 Receivables, net $ 7,293 $ 6,967 December 31 (in millions) 2018 2017 Noncurrent receivables (included in other noncurrent assets, net) $ 1,180 $ 1,093 Noncurrent deferred revenue (included in other noncurrent liabilities) $ 481 $ 392

Programming and Production Cost

Programming and Production Costs	12 Months Ended
	Dec. 31, 2018
Film And Television Cost [Line Items]
Programming and Production Costs	Note 4: Programming and Production Costs Video Distribution Programming Expenses Programming expenses related to video services in Cable Communications and Sky are the fees we pay to license the programming we distribute to our video customers. Programming is generally acquired under multiyear distribution agreements, with rates typically based on the number of customers that receive the programming, channel positioning and the extent of distribution. From time to time, these contracts expire and programming continues to be provided under interim arrangements while the parties negotiate new contract terms, sometimes with effective dates that affect prior periods. While payments are typically made under the prior contract’s terms, the amount of programming expenses recorded during the interim arrangement is based on our estimate of the ultimate contract terms expected to be negotiated. Differences between actual amounts determined upon resolution of negotiations and amounts recorded during these interim arrangements are recorded in the period of resolution. When we receive incentives from a cable network for the licensing of its programming, we defer a portion of these incentives, which are included in other current and noncurrent liabilities, and recognize them over the term of the contract as a reduction to programming expenses. Film and Television Costs Our Cable Networks, Broadcast Television, Filmed Entertainment and Sky segments produce owned content or acquire the rights to programming from third parties, which are described as film and television costs and programming rights, respectively. December 31 (in millions) 2018 2017 Film Costs: Released, less amortization $ 1,600 $ 1,734 Completed, not released 144 50 In production and in development 1,063 1,149 2,807 2,933 Television Costs: Released, less amortization 2,289 2,260 In production and in development 953 818 3,242 3,078 Programming rights, less amortization 5,534 2,689 11,583 8,700 Less: Current portion of programming rights 3,746 1,613 Film and television costs $ 7,837 $ 7,087 Based on our current estimates of the total remaining revenue from all sources (“ultimate revenue”), in 2019 we expect to amortize approximately $1.6 billion of film and television costs associated with our original film and television productions that have been released, or are completed and have not been released. Through 2021, we expect to amortize approximately 83% of unamortized film and television costs for our released productions, excluding amounts allocated to acquired libraries. As of December 31, 2018 , acquired film and television libraries, which are included within the “released, less amortization” captions in the table above, had remaining unamortized costs of $396 million . These costs are generally amortized over a period not to exceed 20 years, and approximately 48% of these costs are expected to be amortized through 2021. Capitalization of Film and Television Costs We capitalize film and television production costs, including direct costs, production overhead, print costs, development costs and interest. We amortize capitalized film and television production costs, including acquired libraries, and accrue costs associated with participation and residual payments to programming and production expenses. We generally record the amortization and the accrued costs using the individual film forecast computation method, which amortizes the costs in the same ratio as the associated ultimate revenue. Estimates of ultimate revenue and total costs are based on anticipated release patterns, public acceptance and historical results for similar productions. Unamortized film and television production costs, including acquired libraries, are stated at the lower of unamortized cost or fair value. We do not capitalize costs related to the distribution of a film in movie theaters or the licensing or sale of a film or television production, which primarily include costs associated with marketing and distribution. In determining the method of amortization and estimated life of an acquired film or television library, we generally use the method and the life that most closely follow the undiscounted cash flows over the estimated life of the asset. When an event or a change in circumstance occurs that was known or knowable as of the balance sheet date and that indicates the fair value of a film is less than its unamortized costs, we determine the fair value of the film and record an impairment charge for the amount by which the unamortized capitalized costs exceed the film’s fair value. The estimated fair value of a production is based on Level 3 inputs that primarily use an analysis of future expected cash flows. Adjustments to capitalized film production costs were not material in any of the periods presented. We may enter into cofinancing arrangements with third parties to jointly finance or distribute certain of our film productions. Cofinancing arrangements can take various forms, but in most cases involve the grant of an economic interest in a film to an investor. The number of investors and the terms of these arrangements can vary, although investors generally assume the full risks and rewards for the portion of the film acquired in these arrangements. We account for the proceeds received from a third-party investor under these arrangements as a reduction to our capitalized film costs. Under these arrangements, the investor owns an undivided copyright interest in the film, and therefore in each period we record either a charge or a benefit to programming and production expenses to reflect the estimate of the third-party investor’s interest in the profit or loss of the film. The estimate of the third-party investor’s interest in the profit or loss of a film is determined using the ratio of actual revenue earned to date to the ultimate revenue expected to be recognized over the film’s useful life. We capitalize the costs of programming content that we license but do not own, including rights to multiyear, live-event sports programming, at the earlier of when payments are made for the programming or when the license period begins and the content is made available for use. We amortize capitalized programming costs as the associated programs are broadcast. We generally amortize multiyear, live-event sports programming rights using the ratio of the current period revenue to the estimated ultimate revenue or under the terms of the contract. Programming costs are recorded at the lower of unamortized cost or net realizable value on a program by program, package, channel or daypart basis. A daypart is an aggregation of programs broadcast during a particular time of day or programs of a similar type. Programming acquired by our Cable Networks segment is primarily tested on a channel basis for impairment, whereas programming acquired by our Broadcast Television segment is tested on a daypart basis. If we determine that the estimates of future cash flows are insufficient or if there is no plan to broadcast certain programming, we recognize an impairment charge to programming and production expenses.
NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Programming and Production Costs	Note 4: Film and Television Costs December 31 (in millions) 2018 2017 Film Costs: Released, less amortization $ 1,600 $ 1,734 Completed, not released 144 50 In production and in development 1,063 1,149 2,807 2,933 Television Costs: Released, less amortization 2,161 2,260 In production and in development 953 818 3,114 3,078 Programming rights, less amortization 2,694 2,677 8,615 8,688 Less: Current portion of programming rights 1,323 1,606 Film and television costs $ 7,292 $ 7,082 Based on our current estimates of the total remaining revenue from all sources (“ultimate revenue”), in 2019 we expect to amortize approximately $1.6 billion of film and television costs associated with our original film and television productions that have been released, or are completed and have not been released. Through 2021, we expect to amortize approximately 83% of unamortized film and television costs for our released productions, excluding amounts allocated to acquired libraries. As of December 31, 2018 , acquired film and television libraries, which are included within the “released, less amortization” captions in the table above, had remaining unamortized costs of $396 million . These costs are generally amortized over a period not to exceed 20 years, and approximately 48% of these costs are expected to be amortized through 2021. Capitalization of Film and Television Costs We capitalize film and television production costs, including direct costs, production overhead, print costs, development costs and interest. We amortize capitalized film and television production costs, including acquired libraries, and accrue costs associated with participation and residual payments to programming and production expenses. We generally record the amortization and the accrued costs using the individual film forecast computation method, which amortizes the costs in the same ratio as the associated ultimate revenue. Estimates of ultimate revenue and total costs are based on anticipated release patterns, public acceptance and historical results for similar productions. Unamortized film and television production costs, including acquired libraries, are stated at the lower of unamortized cost or fair value. We do not capitalize costs related to the distribution of a film in movie theaters or the licensing or sale of a film or television production, which primarily include costs associated with marketing and distribution. In determining the method of amortization and estimated life of an acquired film or television library, we generally use the method and the life that most closely follow the undiscounted cash flows over the estimated life of the asset. When an event or a change in circumstance occurs that was known or knowable as of the balance sheet date and that indicates the fair value of a film is less than its unamortized costs, we determine the fair value of the film and record an impairment charge for the amount by which the unamortized capitalized costs exceed the film’s fair value. The estimated fair value of a production is based on Level 3 inputs that primarily use an analysis of future expected cash flows. Adjustments to capitalized film production costs were not material in any of the periods presented. We may enter into cofinancing arrangements with third parties to jointly finance or distribute certain of our film productions. Cofinancing arrangements can take various forms, but in most cases involve the grant of an economic interest in a film to an investor. The number of investors and the terms of these arrangements can vary, although investors generally assume the full risks and rewards for the portion of the film acquired in these arrangements. We account for the proceeds received from a third-party investor under these arrangements as a reduction to our capitalized film costs. Under these arrangements, the investor owns an undivided copyright interest in the film, and therefore in each period we record either a charge or a benefit to programming and production expenses to reflect the estimate of the third-party investor’s interest in the profit or loss of the film. The estimate of the third-party investor’s interest in the profit or loss of a film is determined using the ratio of actual revenue earned to date to the ultimate revenue expected to be recognized over the film’s useful life. We capitalize the costs of programming content that we license but do not own, including rights to multiyear, live-event sports programming, at the earlier of when payments are made for the programming or when the license period begins and the content is made available for use. We amortize capitalized programming costs as the associated programs are broadcast. We generally amortize multiyear, live-event sports programming rights using the ratio of the current period revenue to the estimated ultimate revenue or under the terms of the contract. Programming costs are recorded at the lower of unamortized cost or net realizable value on a program by program, package, channel or daypart basis. A daypart is an aggregation of programs broadcast during a particular time of day or programs of a similar type. Programming acquired by our Cable Networks segment is primarily tested on a channel basis for impairment, whereas programming acquired by our Broadcast Television segment is tested on a daypart basis. If we determine that the estimates of future cash flows are insufficient or if there is no plan to broadcast certain programming, we recognize an impairment charge to programming and production expenses.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes [Line Items]
Income Taxes	Note 5: Income Taxes Components of Income Tax Expense (Benefit) Year ended December 31 (in millions) 2018 2017 2016 Current Expense (Benefit): Federal $ 2,026 $ 2,411 $ 3,190 State 639 277 480 Foreign 425 389 194 3,090 3,077 3,864 Deferred Expense (Benefit): Federal 546 (10,651 ) 1,183 State (167 ) 11 153 Foreign (89 ) (6 ) 98 290 (10,646 ) 1,434 Income tax expense (benefit) $ 3,380 $ (7,569 ) $ 5,298 Our income tax expense (benefit) differs from the federal statutory amount because of the effect of the items detailed in the table below. Year ended December 31 (in millions) 2018 2017 2016 Federal tax at statutory rate $ 3,201 $ 5,374 $ 5,014 State income taxes, net of federal benefit 212 299 373 Foreign income taxed at different rates 147 70 65 Nontaxable income attributable to noncontrolling interests (20 ) (45 ) (128 ) Adjustments to uncertain and effectively settled tax positions, net 144 (62 ) 24 Accrued interest on uncertain and effectively settled tax positions, net 29 3 17 Excess tax benefits recognized on share-based compensation (75 ) (297 ) — Federal tax legislation (120 ) (12,682 ) — Other (138 ) (229 ) (67 ) Income tax expense (benefit) $ 3,380 $ (7,569 ) $ 5,298 We base our provision for income taxes on our current period income, changes in our deferred income tax assets and liabilities, income tax rates, changes in estimates of our uncertain tax positions, tax planning opportunities available in the jurisdictions in which we operate and following the adoption of new accounting guidance related to share-based compensation in 2017, excess tax benefits or deficiencies that arise when the tax consequences of share-based compensation differ from amounts previously recognized in the statement of income. We recognize deferred tax assets and liabilities when there are temporary differences between the financial reporting basis and tax basis of our assets and liabilities and for the expected benefits of using net operating loss carryforwards. When a change in the tax rate or tax law has an impact on deferred taxes, we apply the change based on the years in which the temporary differences are expected to reverse. We record the change in our consolidated financial statements in the period of enactment. The determination of the income tax consequences of a business combination includes identifying the tax basis of assets and liabilities acquired and any contingencies associated with uncertain tax positions assumed or resulting from the business combination. Deferred tax assets and liabilities related to temporary differences of an acquired entity are recorded as of the date of the business combination and are based on our estimate of the ultimate tax basis that will be accepted by the various tax authorities. We record liabilities for contingencies associated with prior tax returns filed by the acquired entity based on criteria set forth in the appropriate accounting guidance. We adjust the deferred tax accounts and the liabilities periodically to reflect any revised estimated tax basis and any estimated settlements with the various tax authorities. The effects of these adjustments are recorded to income tax expense (benefit). From time to time, we engage in transactions in which the tax consequences may be subject to uncertainty. In these cases, we evaluate our tax position using the recognition threshold and the measurement attribute in accordance with the accounting guidance related to uncertain tax positions. Examples of these transactions include business acquisitions and dispositions, including consideration paid or received in connection with these transactions, certain financing transactions, and the allocation of income among state and local tax jurisdictions. Significant judgment is required in assessing and estimating the tax consequences of these transactions. We determine whether it is more likely than not that a tax position will be sustained on examination, including the resolution of any related appeals or litigation processes, based on the technical merits of the position. A tax position that meets the more-likely-than-not recognition threshold is measured to determine the amount of benefit to be recognized in our consolidated financial statements. We classify interest and penalties, if any, associated with our uncertain tax positions as a component of income tax expense (benefit). Current and deferred foreign income taxes are incurred primarily by Sky’s and NBCUniversal’s foreign subsidiaries. In 2018 , 2017 and 2016 , we had foreign income before taxes of $855 million , $1 billion and $871 million , respectively, on which foreign income tax expense (benefit) was recorded. Sky Acquisition We recorded a $1.9 billion increase in deferred income tax liabilities in connection with the acquisition of Sky, which were primarily related to foreign temporary differences associated with intangible assets and net operating losses, and were included in the preliminary allocation of purchase price. Although it operates primarily outside the United States, Sky will be included in certain of our consolidated state tax returns, which impacted our effective tax rates in those jurisdictions. As a result, we also recorded a $244 million net decrease in the deferred state tax liability, net of federal benefit, on our existing temporary differences, which was included in income tax expense in the fourth quarter of 2018. Tax Reform On December 22, 2017, new federal tax reform legislation was enacted in the United States, resulting in significant changes from previous tax law. The 2017 Tax Act reduced the federal corporate income tax rate to 21% from 35% effective January 1, 2018. The rate change, along with certain immaterial changes in tax basis resulting from the 2017 Tax Act, resulted in a reduction of our net deferred tax liabilities of $12.4 billion and a corresponding deferred income tax benefit in 2017. Our federal income tax expense for periods beginning in 2018 was based on the new rate. The 2017 Tax Act also changed the taxation of foreign earnings, and companies generally are not subject to United States federal income taxes upon the receipt of dividends from foreign subsidiaries and are not permitted foreign tax credits related to such dividends. Beginning in 2018, in general, we no longer record United States federal income tax on our share of the income of our foreign subsidiaries, and we no longer record a benefit for foreign tax credits related to that income. Upon enactment, we reversed $382 million of net deferred tax liabilities related to our cumulative undistributed foreign earnings and deferred tax assets for related foreign tax credits, resulting in a corresponding net tax benefit in 2017. Additionally, upon enactment, there was a one-time deemed repatriation tax on undistributed foreign earnings and profits (the “transition tax”). We recognized tax expense of $101 million related to the transition tax in 2017. The 2017 Tax Act also provides for immediate deduction of 100% of the costs of qualified property, including significant portions of our capital expenditures and film and television productions costs, that are incurred and the property placed in service during the period from September 27, 2017 to December 31, 2022. This provision will begin to phase down by 20% per year beginning January 1, 2023 and will be completely phased out as of January 1, 2027. The adjustments to deferred tax assets and liabilities, and the liability related to the transition tax included provisional amounts estimated based on information available as of December 31, 2017. In 2018, we completed our analysis of the provisional items, resulting in immaterial adjustments primarily related to cumulative temporary differences and the one-time deemed repatriation tax on undistributed foreign earnings and profits. In February 2018, the Bipartisan Budget Act of 2018 was enacted. As part of this legislation, various tax provisions that had expired on December 31, 2016 were retroactively extended to December 31, 2017, including the statute permitting the immediate deduction for certain film and television production costs. We recorded an income tax benefit of $128 million in the first quarter of 2018 as a result of the enactment of this legislation. Components of Net Deferred Tax Liability December 31 (in millions) 2018 2017 Deferred Tax Assets: Net operating loss carryforwards $ 1,926 $ 481 Nondeductible accruals and other 2,656 2,092 Less: Valuation allowance 632 377 3,950 2,196 Deferred Tax Liabilities: Differences between book and tax basis of property and equipment and intangible assets 29,139 25,223 Differences between book and tax basis of investments 491 466 Differences between book and tax basis of long-term debt 604 673 Differences between book and tax basis of foreign subsidiaries and undistributed foreign earnings 85 39 30,319 26,401 Net deferred tax liability $ 26,369 $ 24,205 Changes in our net deferred tax liability in 2018 that were not recorded as deferred income tax benefit (expense) are primarily related to increases of $1.9 billion related to acquisitions, including Sky, and $42 million associated with our purchase of a noncontrolling interest, and a decrease of $72 million associated with items included in other comprehensive income (loss). Our net deferred tax liability includes $15 billion related to cable franchise rights that will remain unchanged unless we recognize an impairment or dispose of a cable franchise or there is a change in the tax law. Additionally, we recorded an immaterial cumulative effect adjustment to retained earnings and accumulated other comprehensive income (loss) in 2018 as a result of the adoption of updated guidance that permitted companies to reclassify disproportionate tax effects recorded in accumulated other comprehensive income as a result of the 2017 Tax Act. As of December 31, 2018 , we had federal net operating loss carryforwards of $268 million , and various state net operating loss carryforwards, the majority of which expire in periods through 2038. As of December 31, 2018 , we also had foreign net operating loss carryforwards of $6.6 billion related to the foreign operations of Sky and NBCUniversal, the majority of which can be carried forward indefinitely. The determination of the realization of the state and foreign net operating loss carryforwards is dependent on our subsidiaries’ taxable income or loss, apportionment percentages, redetermination from taxing authorities, and state and foreign laws that can change from year to year and impact the amount of such carryforwards. We recognize a valuation allowance if we determine it is more likely than not that some portion, or all, of a deferred tax asset will not be realized. As of December 31, 2018 and 2017 , our valuation allowance was primarily related to state and foreign net operating loss carryforwards. The increase in the valuation allowance in 2018 was primarily related to the acquisition of Sky. As a result of the timing of the acquisition, the deferred tax assets and liabilities related to Sky are preliminary and subject to change, including our assessment of the realization of Sky’s deferred tax assets of $1.5 billion related to net operating losses. We will finalize the amounts recognized as soon as possible as we obtain the information necessary to complete the analysis, but no later than one year from the acquisition date. See Note 8 for further information on the Sky acquisition. Uncertain Tax Positions Our liability for uncertain tax positions as of December 31, 2018 totaled $1.0 billion , which excludes the federal benefits on state tax positions that were recorded as deferred income taxes. Included in our liability for uncertain tax positions was $153 million related to tax positions of NBCUniversal and NBCUniversal Enterprise for which we have been indemnified by GE, their former parent company. We are indemnified by GE for any income tax liability attributable to the NBCUniversal contributed businesses for periods prior to the close of the NBCUniversal transaction in January 2011 and also for any income tax liability attributable to NBCUniversal Enterprise for periods prior to the date of the NBCUniversal redemption transaction in March 2013. Reconciliation of Unrecognized Tax Benefits (in millions) 2018 2017 2016 Gross unrecognized tax benefits, January 1 $ 1,497 $ 1,443 $ 1,441 Additions based on tax positions related to the current year 229 121 74 Additions based on tax positions related to prior years 125 319 72 Additions from acquired subsidiaries 130 — 13 Reductions for tax positions of prior years (346 ) (251 ) (66 ) Reductions due to expiration of statutes of limitations (75 ) (70 ) (44 ) Settlements with tax authorities (17 ) (65 ) (47 ) Gross unrecognized tax benefits, December 31 1,543 1,497 1,443 Positions paid (531 ) (688 ) (340 ) Liability for uncertain tax positions $ 1,012 $ 809 $ 1,103 Our liability for uncertain tax positions represents the amounts recorded for potential payment obligations. Our gross unrecognized tax benefits also include amounts related to positions for which tax has been assessed and paid. If we were to recognize our gross unrecognized tax benefits in the future, $ 1.1 billion , which includes amounts indemnified by GE, would impact our effective tax rate and the remaining amount would increase our deferred income tax liability. The amount and timing of the recognition of any such tax benefit is dependent on the completion of examinations of our tax filings by the various tax authorities and the expiration of statutes of limitations. It is reasonably possible that certain tax contests could be resolved within the next 12 months that may result in a decrease in our effective tax rate. As of December 31, 2018 and 2017 , our accrued interest associated with our liability for uncertain tax positions was $203 million and $173 million , respectively. As of December 31, 2018 and 2017 , $56 million and $43 million , respectively, of these amounts were related to tax positions of NBCUniversal and NBCUniversal Enterprise for which we have been indemnified by GE. The IRS has completed its examination of our income tax returns for all years through 2016. Various states are examining our state tax returns and the tax years of those tax returns currently under examination vary by state, with most of the periods relating to tax years 2000 and forward. Various foreign jurisdictions are examining our tax returns and the tax years of those tax returns currently under examination vary by country, with most of the periods relating to tax years 2010 and forward.
NBCUniversal Media LLC [Member]
Income Taxes [Line Items]
Income Taxes	Note 5: Income Taxes Components of Income Tax Expense Year ended December 31 (in millions) 2018 2017 2016 Foreign Current income tax expense $ 230 $ 201 $ 38 Deferred income tax expense (31 ) (7 ) 96 Withholding tax expense 163 187 158 U.S. domestic tax expense (11 ) 11 13 Income tax expense $ 351 $ 392 $ 305 We are a limited liability company, and our company is disregarded for U.S. federal income tax purposes as an entity separate from NBCUniversal Holdings, a tax partnership. For U.S federal and state income tax purposes, our income is included in tax returns filed by Comcast and its subsidiaries, and therefore we are not expected to incur any significant current or deferred U.S. domestic income taxes. Our tax liability is comprised primarily of withholding tax on foreign licensing activity and income taxes on foreign earnings. As a result of our tax status, the deferred tax assets and liabilities included in our consolidated balance sheet at December 31, 2018 and 2017 were not material. In jurisdictions in which we are subject to income taxes, we base our provision for income taxes on our current period income, changes in our deferred income tax assets and liabilities, income tax rates, changes in estimates of our uncertain tax positions, and tax planning opportunities available in the jurisdictions in which we operate. We recognize deferred tax assets and liabilities when there are temporary differences between the financial reporting basis and tax basis of our assets and liabilities and for the expected benefits of using net operating loss carryforwards. When a change in the tax rate or tax law has an impact on deferred taxes, we apply the change based on the years in which the temporary differences are expected to reverse. We record the change in our consolidated financial statements in the period of enactment. We classify interest and penalties, if any, associated with our uncertain tax positions as a component of income tax expense. Uncertain Tax Positions We retain liabilities for uncertain tax positions where we are the tax filer of record. GE and Comcast have indemnified NBCUniversal Holdings and us with respect to our income tax obligations attributable to periods prior to Comcast’s acquisition of NBCUniversal, including indemnification of uncertain tax positions for these periods. The liabilities for uncertain tax positions included in our consolidated balance sheet were not material as of December 31, 2018 and 2017 . Various domestic and foreign tax authorities are examining our tax returns through tax year 2017. The majority of the periods under examination relate to tax years 2010 and forward.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Note 6: Earnings Per Share Computation of Diluted EPS 2018 2017 2016 Year ended December 31 Net Income Shares Per Share Net Income Shares Per Share Net Income Shares Per Share Basic EPS attributable to Comcast Corporation shareholders $ 11,731 4,584 $ 2.56 $ 22,735 4,708 $ 4.83 $ 8,678 4,819 $ 1.80 Effect of dilutive securities: Assumed exercise or issuance of shares relating to stock plans 56 78 56 Diluted EPS attributable to Comcast Corporation shareholders $ 11,731 4,640 $ 2.53 $ 22,735 4,786 $ 4.75 $ 8,678 4,875 $ 1.78 Diluted earnings per common share attributable to Comcast Corporation shareholders (“diluted EPS”) considers the impact of potentially dilutive securities using the treasury stock method. Our potentially dilutive securities include potential common shares related to our stock options and our restricted share units (“RSUs”). Diluted EPS excludes the impact of potential common shares related to our stock options in periods in which the combination of the option exercise price and the associated unrecognized compensation expense is greater than the average market price of our common stock. The amount of potential common shares related to our share-based compensation plans that were excluded from diluted EPS because their effect would have been antidilutive was not material in any of the periods presented.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Debt Instrument [Line Items]
Long-Term Debt	Note 7: Long-Term Debt Long-Term Debt Outstanding December 31 (in millions) Weighted-Average 2018 2017 Commercial paper 2.86 % $ 675 $ 903 Revolving bank credit facilities (b) 1.13 % 606 — Term loans (a) 1.85 % 13,268 3,880 Senior notes with maturities of 5 years or less, at face value (b) 3.48 % 26,331 15,680 Senior notes with maturities between 5 and 10 years, at face value (b) 3.64 % 26,727 13,277 Senior notes with maturities greater than 10 years, at face value (b)(c) 4.68 % 45,030 31,838 Other, including capital lease obligations — 808 921 Debt issuance costs, premiums, discounts, fair value adjustments for acquisition accounting and hedged positions, net (d) — (1,702 ) (1,943 ) Total debt 3.77 % (d) 111,743 64,556 Less: Current portion 4,398 5,134 Long-term debt $ 107,345 $ 59,422 (a) Term loans consist of the following, with foreign currency denominated borrowings translated using the exchange rates as of each date: • Comcast: borrowings associated with the Sky transaction of £5.6 billion as of December 31, 2018 (see Note 8) • Universal Studios Japan: ¥390 billion and ¥435 billion as of December 31, 2018 and 2017 , respectively • Universal Beijing Resort: ¥4 billion RMB as of December 31, 2018 (see Note 8) (b) The December 31, 2018 amounts include an aggregate of approximately $10.7 billion of Sky debt consolidated by Comcast. The Sky debt as of December 31, 2018 included $3.2 billion of senior notes, €4.9 billion of senior notes and £1.1 billion of senior notes that will mature between 2019 and 2035. The Sky senior notes were recorded at fair value as of October 9, 2018. (c) The December 31, 2018 and 2017 amounts include £625 million of 5.50% notes due 2029. (d) Includes the effects of our derivative financial instruments. As of December 31, 2018 and 2017 , our debt had an estimated fair value of $114.1 billion and $71.7 billion , respectively. The estimated fair value of our publicly traded debt was primarily based on Level 1 inputs that use quoted market values for the debt. The estimated fair value of debt for which there are no quoted market prices was based on Level 2 inputs that use interest rates available to us for debt with similar terms and remaining maturities. We use cross-currency swaps for foreign currency denominated debt obligations when those obligations are denominated in a currency other than the functional currency. Cross-currency swaps effectively convert foreign currency denominated debt to debt denominated in the functional currency in order to hedge the risk that the cash flows related to annual interest payments and the payment of principal at maturity may be adversely affected by fluctuations in currency exchange rates. The gains and losses on these cross-currency swaps generally offset changes in the underlying value of the related exposures. As of December 31, 2018 and 2017 , we had cross-currency swaps on $5.3 billion and $0.8 billion notional amount of our foreign currency denominated debt, respectively. As of December 31, 2018 and 2017 , the aggregate fair value of these cross-currency swaps was a net liability of $23 million and $80 million , respectively. We are also exposed to foreign currency exchange risk on the consolidation of our foreign operations. Beginning in 2018, we use foreign currency denominated debt and cross-currency swaps to hedge our net investments in certain of these subsidiaries. As of December 31, 2018 , we had $15.6 billion notional amount of our foreign currency denominated debt and cross-currency swaps designated as net investment hedges in our foreign subsidiaries. Principal Maturities of Debt (in millions) 2019 $ 4,413 2020 $ 7,961 2021 $ 11,548 2022 $ 8,741 2023 $ 7,818 Thereafter $ 72,964 2018 Debt Borrowings and Repayments In 2018 , we had borrowings of $44.8 billion that primarily included $27 billion of proceeds from the issuance of senior unsecured fixed and floating rate notes in October 2018, $8.7 billion of proceeds from sterling-denominated unsecured term loans and $3 billion of proceeds from the dollar-denominated unsecured term loan which were used to fund the acquisition of Sky, and $4 billion of proceeds from the issuance of senior unsecured fixed rate notes in February 2018. In 2018, we made repayments of $8.8 billion of debt. Revolving Bank Credit Facilities As of December 31, 2018 and 2017 , we had a $7.6 billion and $7.0 billion , respectively, revolving credit facility due 2021 with a syndicate of banks (“Comcast revolving credit facility”) that may be used for general corporate purposes. We may increase the commitment under the Comcast revolving credit facility up to a total of $10 billion , as well as extend the expiration date to a date no later than 2023, subject to approval of the lenders. In addition, as of December 31, 2018 and 2017 , NBCUniversal Enterprise had a $1.6 billion and $1.5 billion , respectively, revolving credit facility due 2021 with a syndicate of banks (“NBCUniversal Enterprise revolving credit facility”) that may be used for general corporate purposes. We may increase the commitment under the NBCUniversal Enterprise revolving credit facility up to a total of $2 billion , as well as extend the expiration date to a date no later than 2023, subject to approval of the lenders. The interest rates on the revolving credit facilities consist of a base rate plus a borrowing margin that is determined based on Comcast’s credit rating. As of December 31, 2018 , the borrowing margin for borrowings based on the London Interbank Offered Rate was 1.00% . As of December 31, 2018 , Sky had a £1 billion revolving credit facility due 2021 with a syndicate of banks (“Sky revolving credit facility”) that may be used for general corporate purposes. The interest rate on the Sky revolving credit facility consists of a base rate plus a borrowing margin that is determined based on Sky’s credit rating. Each of the revolving credit facilities requires that we maintain certain financial ratios based on the respective debt and EBITDA of each entity, as defined in the credit facility. The Sky revolving credit facility also contains a ratio of EBITDA to net interest payable, as defined in the credit facility. We were in compliance with all financial covenants for all periods presented. There were no amounts outstanding under the Comcast or NBCUniversal Enterprise revolving credit facilities as of December 31, 2018 or 2017 . As of December 31, 2018 , £475 million (approximately $606 million using exchange rates as of December 31, 2018) was outstanding under the Sky revolving credit facility. As of December 31, 2018 , amounts available under our consolidated revolving credit facilities, net of amounts outstanding under our commercial paper programs and outstanding letters of credit, totaled $9.2 billion , which included $942 million and $670 million available under the NBCUniversal Enterprise and Sky revolving credit facilities, respectively. Commercial Paper Programs Our commercial paper programs provide a lower-cost source of borrowing to fund our short-term working capital requirements. In June 2017, we increased the Comcast and NBCUniversal Enterprise commercial paper programs to $7.0 billion and $1.5 billion , respectively, to coincide with the borrowing capacities then existing under the Comcast and NBCUniversal Enterprise revolving credit facilities. As of December 31, 2018 , there was no amount outstanding under the Comcast commercial paper program. As of December 31, 2017 , $903 million was outstanding under the Comcast commercial paper program. As of December 31, 2018 , NBCUniversal Enterprise had $675 million face amount of commercial paper outstanding. As of December 31, 2017 , NBCUniversal Enterprise had no commercial paper outstanding. Letters of Credit and Bank Guarantees As of December 31, 2018 , we and certain of our subsidiaries had undrawn irrevocable standby letters of credit and bank guarantees totaling $463 million to cover potential fundings under various agreements. Cross-Guarantee Structure Comcast, Comcast Cable and NBCUniversal have fully and unconditionally guaranteed each other’s debt securities, including the Comcast revolving credit facility and the term loans borrowed and senior notes issued in connection with financing the acquisition of Sky. As of December 31, 2018 , the principal amount of debt securities within the cross-guarantee structure totaled $94.2 billion , of which $26.9 billion will mature within the next 5 years . Comcast and Comcast Cable fully and unconditionally guarantee NBCUniversal Enterprise’s $3.0 billion aggregate principal amount of senior notes, its revolving credit facility and its commercial paper program. NBCUniversal does not guarantee the NBCUniversal Enterprise senior notes, revolving credit facility, commercial paper program or its $725 million liquidation preference of Series A cumulative preferred stock. Comcast Parent provides a full and unconditional guarantee of the Universal Studios Japan yen-denominated ¥390 billion (approximately $ 3.5 billion using exchange rates as of December 31, 2018 ) term loans with a final maturity of March 2022. None of Comcast, Comcast Cable nor NBCUniversal guarantee the $10.7 billion of Sky outstanding indebtedness or the $569 million of Universal Beijing Resort term loans.
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Long-Term Debt	Note 6: Long-Term Debt Long-Term Debt Outstanding December 31 (in millions) Weighted-Average Interest Rate as of December 31, 2018 2018 2017 Term loans (a) 1.30 % $ 4,122 $ 3,860 Senior notes with maturities of 5 years or less, at face value 4.39 % 5,000 4,000 Senior notes with maturities between 5 and 10 years, at face value — — 1,000 Senior notes with maturities greater than 10 years, at face value 5.50 % 2,759 2,759 Notes due 2049 to Comcast 4.00 % 610 610 Other, including capital lease obligations — 427 276 Debt issuance costs, premiums and discounts, net — (36 ) (32 ) Total debt 3.58 % 12,882 12,473 Less: Current portion 151 198 Long-term debt $ 12,731 $ 12,275 (a) Term loans consist of the following, with foreign currency denominated borrowings translated using the exchange rates as of each date: • Universal Studios Japan: ¥390 billion and ¥435 billion as of December 31, 2018 and 2017 , respectively • Universal Beijing Resort: ¥4 billion RMB as of December 31, 2018 (see Note 7) As of December 31, 2018 and 2017 , our debt, excluding our revolving credit agreement with Comcast, had an estimated fair value of $13.2 billion and $13.5 billion , respectively. The estimated fair value of our publicly traded debt was primarily based on Level 1 inputs that use quoted market values for the debt. The estimated fair value of debt for which there are no quoted market prices was based on Level 2 inputs that use interest rates available to us for debt with similar terms and remaining maturities. Principal Maturities of Debt (in millions) 2019 $ 153 2020 $ 2,280 2021 $ 2,365 2022 $ 2,922 2023 $ 1,012 Thereafter $ 4,186 Cross-Guarantee Structure We, Comcast and a 100% owned cable holding company subsidiary of Comcast (“CCCL Parent”) fully and unconditionally guarantee each other’s debt securities, including the $7.6 billion Comcast revolving credit facility due 2021 and the $27.0 billion of Comcast senior unsecured fixed and floating rate notes issued in connection with Comcast’s acquisition of Sky. As of December 31, 2018 , outstanding debt securities of $86.4 billion of Comcast and CCCL Parent were subject to the cross-guarantee structure. We do not, however, guarantee the obligations of NBCUniversal Enterprise with respect to its $3.0 billion aggregate principal amount of senior notes, its revolving credit facility, its commercial paper program, nor its $725 million liquidation preference of Series A cumulative preferred stock. The Universal Studios Japan term loans are not subject to the cross-guarantee structure, however they have a separate guarantee from Comcast. The Universal Beijing Resort term loans are not guaranteed.

Significant Transactions

Significant Transactions	12 Months Ended
	Dec. 31, 2018
Business Acquisition [Line Items]
Significant Transactions	Note 8: Significant Transactions 2018 Sky Transaction On October 9, 2018, in connection with our offer to acquire the share capital of Sky, we acquired a controlling interest in Sky through a series of purchases of Sky shares at our offer price of £17.28 per Sky share. In the fourth quarter of 2018, we acquired the remaining Sky shares and now own 100% of Sky’s equity interests. Total cash consideration was £30.2 billion (approximately $39.4 billion using the exchange rates on the purchase dates). Sky is one of Europe’s leading entertainment companies, which primarily includes a direct-to-consumer business, providing video, high-speed internet, voice and wireless phone services, and a content business, operating entertainment networks, the Sky News broadcast network and Sky Sports networks. We believe the combination of our global communications, media and entertainment businesses will enable the delivery of innovations in technology and a strengthened content portfolio to an expanded worldwide audience across multiple platforms. To finance the acquisition, we issued $27.0 billion aggregate amount of senior unsecured fixed and floating rate notes that will mature between 2020 and 2058 and we borrowed £6.6 billion ( $8.7 billion using the exchange rates on the dates of borrowing) under a £7.0 billion unsecured sterling-denominated term loan credit agreement and $3.0 billion under a $3.0 billion unsecured dollar-denominated term loan credit agreement. The unsecured term loans and senior notes are guaranteed by Comcast Cable and NBCUniversal. The remaining amount of consideration was funded using cash on hand. Preliminary Allocation of Purchase Price We have applied acquisition accounting to Sky. Sky’s results of operations are included in our consolidated results of operations since the acquisition date and are reported in our Sky segment. The net assets of Sky were recorded at their estimated fair value using Level 3 inputs. In valuing acquired assets and liabilities, fair value estimates are based on, but are not limited to, future expected cash flows, market rate assumptions for contractual obligations and appropriate discount rates. The estimated values are not yet final and are subject to change, and the changes could be significant. We will finalize the amounts recognized as soon as possible as we obtain the information necessary to complete the analysis, but no later than one year from the acquisition date. The table below presents the preliminary allocation of the all-cash purchase price of £30.2 billion , or $39.4 billion , to the assets and liabilities of Sky as a result of the transaction. Preliminary Allocation of Purchase Price (in millions) Consideration transferred $ 39,387 Preliminary allocation of purchase price Cash $ 1,283 Accounts receivable and other current assets 2,405 Film and television costs (See Note 4) 2,526 Property and equipment (See Note 11) 3,386 Intangible assets (See Note 12) 20,628 Accounts payable, accrued liabilities and other current liabilities (5,791 ) Long-term debt (See Note 7) (11,215 ) Deferred tax assets (liabilities), net (See Note 5) (1,903 ) Other noncurrent assets and (liabilities), net (1,809 ) Fair value of identifiable net assets acquired 9,510 Goodwill (See Note 12) $ 29,877 Intangible Assets Finite-lived intangible assets primarily consist of customer relationships with a carrying amount of $11.8 billion and developed technology with a carrying amount of $1.8 billion , with estimated useful lives of between 4 and 18 years . Indefinite-lived assets consist of trade names with a carrying amount of $6.8 billion . Goodwill Goodwill consists primarily of intangible assets that do not qualify for separate recognition, including increased footprint, assembled workforce, noncontractual relationships and agreements. Since our allocation of the purchase price and estimated fair values of identifiable assets and liabilities is not yet final, the amount of the total goodwill is not yet final and is subject to change. The acquired goodwill is not expected to be deductible for tax purposes. Acquisition-Related Costs As a result of the Sky transaction, we have incurred incremental expenses including the U.K. share acquisition tax, success-based investment banker fees and fees to attorneys, accountants and other professional advisors, which are reflected in other operating and administrative expenses. We also incurred certain financing costs associated with our borrowings, which are reflected in interest expense. The table below presents the amounts related to these expenses included in our consolidated statement of income. (in millions) Year ended December 31, 2018 Other operating and administrative expenses $ 339 Interest expense $ 63 Actual and Unaudited Pro Forma Information Our consolidated revenue and net income (loss) attributable to Comcast Corporation from October 9, 2018 to December 31, 2018 included $4.6 billion and $47.5 million , respectively, resulting from Sky’s operations. The following unaudited pro forma information has been presented as if the Sky transaction occurred on January 1, 2017. This information is based on historical results of operations, adjusted for allocation of purchase price and other acquisition accounting adjustments, and is not necessarily indicative of what the results would have been had we operated the business since January 1, 2017. For pro forma purposes, 2018 earnings were adjusted to exclude the acquisition-related costs noted above, and 2017 earnings were adjusted to include these costs. No pro forma adjustments have been made for cost savings or synergies that have been or may be achieved by the combined businesses. Year ended December 31 (in millions, except per share data) 2018 2017 Revenue $ 109,518 $ 102,971 Net income attributable to Comcast Corporation $ 11,365 $ 22,308 Basic earnings per common share attributable to Comcast Corporation shareholders $ 2.48 $ 4.74 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 2.45 $ 4.65 Universal Beijing Resort We entered into an agreement with a consortium of Chinese state-owned companies to build and operate a Universal theme park and resort in Beijing, China (“Universal Beijing Resort”). We own a 30% interest in Universal Beijing Resort and the construction is being funded through a combination of debt financing and equity contributions from the investors in accordance with their equity interests. The debt financing, which is being provided by a syndicate of Chinese financial institutions, contains certain financial and operating covenants and a maximum borrowing limit of ¥ 26.6 billion RMB (approximately $4 billion ). The debt financing is secured by the assets of Universal Beijing Resort and the equity interests of the investors. As of December 31, 2018 , Universal Beijing Resort had borrowed approximately $569 million under the financing agreement. We have concluded that Universal Beijing Resort is a variable interest entity based on its governance structure, and we consolidate it because we have the power to direct activities that most significantly impact its economic performance. There are no liquidity arrangements, guarantees or other financial commitments between us and Universal Beijing Resort, and therefore our maximum risk of financial loss is our 30% interest. Universal Beijing Resort’s results of operations are reported in our Theme Parks segment. In March 2018, Universal Beijing Resort received initial equity investments through a combination of cash and noncash contributions from the investors. As of December 31, 2018 , our consolidated balance sheet included assets, primarily including property and equipment, and liabilities of Universal Beijing Resort totaling $1.5 billion and $1.0 billion , respectively. 2017 FCC Spectrum Auction On April 13, 2017, the Federal Communications Commission announced the results of its spectrum auction. In the auction, NBCUniversal relinquished its spectrum rights in the New York, Philadelphia and Chicago designated market areas (“DMAs”) where NBC and Telemundo had overlapping spectrum. NBCUniversal received proceeds of $482 million in July 2017, which were recorded in other investing activities in our consolidated statement of cash flows. NBCUniversal recognized a pretax gain of $337 million in other operating gains in 2017. NBC and Telemundo stations share broadcast signals in these DMAs. In connection with the auction, we also acquired the rights to $1.7 billion of spectrum in the second quarter of 2017, which were recorded to other intangible assets, net. We had previously made a deposit of $1.8 billion to participate in the auction in 2016 and received a refund for amounts in excess of the purchase price in 2017. Universal Studios Japan On April 6, 2017, we acquired the remaining interests in Universal Studios Japan that we did not already own for $2.3 billion . The acquisition was funded through cash on hand and borrowings under our commercial paper program. Because we maintained control of Universal Studios Japan, the difference between the consideration transferred and the recorded value of the noncontrolling interests, as well as the related tax and accumulated other comprehensive income impacts, were recorded to additional paid-in capital. 2016 DreamWorks Animation On August 22, 2016, we acquired all of the outstanding stock of DreamWorks Animation for $3.8 billion . DreamWorks Animation’s stockholders received $41 in cash for each share of DreamWorks Animation common stock. DreamWorks Animation creates animated feature films, television series and specials, live entertainment, and related consumer products. The results of operations for DreamWorks Animation are reported in our Filmed Entertainment segment following the acquisition date.
NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Significant Transactions	Note 7: Significant Transactions 2018 Universal Beijing Resort We entered into an agreement with a consortium of Chinese state-owned companies to build and operate a Universal theme park and resort in Beijing, China (“Universal Beijing Resort”). We own a 30% interest in Universal Beijing Resort and the construction is being funded through a combination of debt financing and equity contributions from the investors in accordance with their equity interests. The debt financing, which is being provided by a syndicate of Chinese financial institutions, contains certain financial and operating covenants and a maximum borrowing limit of ¥ 26.6 billion RMB (approximately $4 billion ). The debt financing is secured by the assets of Universal Beijing Resort and the equity interests of the investors. As of December 31, 2018, Universal Beijing Resort had borrowed approximately $569 million under the financing agreement. We have concluded that Universal Beijing Resort is a variable interest entity based on its governance structure, and we consolidate it because we have the power to direct activities that most significantly impact its economic performance. There are no liquidity arrangements, guarantees or other financial commitments between us and Universal Beijing Resort, and therefore our maximum risk of financial loss is our 30% interest. Universal Beijing Resort’s results of operations are reported in our Theme Parks segment. In March 2018, Universal Beijing Resort received initial equity investments through a combination of cash and noncash contributions from the investors. As of December 31, 2018, our consolidated balance sheet included assets, primarily including property and equipment, and liabilities of Universal Beijing Resort totaling $1.5 billion and $1.0 billion , respectively. 2017 FCC Spectrum Auction On April 13, 2017, the Federal Communications Commission announced the results of its spectrum auction. In the auction, we relinquished our spectrum rights in the New York, Philadelphia and Chicago designated market areas (“DMAs”) where NBC and Telemundo had overlapping spectrum. We received proceeds of $482 million in July 2017, which were recorded in other investing activities in our consolidated statement of cash flows. We recognized a pretax gain of $337 million in other operating gains in 2017. NBC and Telemundo stations share broadcast signals in these DMAs. Universal Studios Japan On April 6, 2017, we acquired the remaining interests in Universal Studios Japan that we did not already own for $2.3 billion . The acquisition was funded through borrowings under our revolving credit agreement with Comcast. Because we maintained control of Universal Studios Japan, the difference between the consideration transferred and the recorded value of the noncontrolling interests, as well as the related accumulated other comprehensive income impacts, were recorded to additional paid-in capital. 2016 DreamWorks Animation On August 22, 2016, Comcast acquired all of the outstanding stock of DreamWorks Animation for $3.8 billion . DreamWorks Animation’s stockholders received $41 in cash for each share of DreamWorks Animation common stock. DreamWorks Animation creates animated feature films, television series and specials, live entertainment, and related consumer products. In our allocation of purchase price for this acquisition, we recorded goodwill of $2.8 billion and film and television costs of $838 million . Following the acquisition, Comcast converted DreamWorks Animation to a limited liability company and contributed its equity to us as a capital contribution. The net assets contributed to us excluded deferred income taxes and other tax-related items recorded by Comcast. The results of operations for DreamWorks Animation are reported in our Filmed Entertainment segment following the acquisition date and are presented as if the initial equity contribution occurred on the date of Comcast’s acquisition.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Recent Accounting Pronouncements and Tax Reform	Note 9: Recent Accounting Pronouncements Revenue Recognition In May 2014, the Financial Accounting Standards Board (“FASB”) updated the accounting guidance related to revenue recognition. The updated accounting guidance provides a single, contract-based revenue recognition model to help improve financial reporting by providing clearer guidance on when an entity should recognize revenue and by reducing the number of standards to which an entity has to refer. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the updated guidance on January 1, 2018 on a full retrospective basis, which required us to reflect the impact of the updated guidance for all periods presented. Upon adoption, we also implemented changes in our presentation of certain revenues and expenses, primarily in our Cable Communications segment. The adoption of the new standard did not have a material impact on our consolidated results of operations or financial position for any period presented. The updated guidance also requires additional disclosures regarding the nature, timing and uncertainty of our revenue transactions. See Note 3 for additional information. The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 84,526 $ 503 $ 85,029 Total costs and expenses $ 66,539 $ 472 $ 67,011 Operating income $ 17,987 $ 31 $ 18,018 Net income attributable to Comcast Corporation $ 22,714 $ 21 $ 22,735 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 80,403 $ 333 $ 80,736 Total costs and expenses $ 63,544 $ 361 $ 63,905 Operating income $ 16,859 $ (28 ) $ 16,831 Net income attributable to Comcast Corporation $ 8,695 $ (17 ) $ 8,678 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 16,060 $ 283 $ 16,343 Film and television costs $ 7,076 $ 11 $ 7,087 Other intangible assets, net $ 18,779 $ (646 ) $ 18,133 Other noncurrent assets, net $ 3,489 $ 865 $ 4,354 Total assets $ 186,949 $ 513 $ 187,462 Total current liabilities $ 21,561 $ 432 $ 21,993 Deferred income taxes $ 24,256 $ 3 $ 24,259 Other noncurrent liabilities $ 10,904 $ 68 $ 10,972 Total equity $ 69,449 $ 10 $ 69,459 Total liabilities and equity $ 186,949 $ 513 $ 187,462 Cable Communications A summary of the changes implemented for the Cable Communications segment is presented below. Changes to Presentation of Revenue and Related Costs • Revenue from our residential video services decreased with corresponding increases to high-speed internet and voice revenue due to a change in the allocation of revenue among our cable services included in a bundle that our residential customers purchase at a discount. • Revenue from franchise and other regulatory fees, which was previously presented in other revenue, is now presented with the corresponding cable services. This resulted in increases to video, voice and business services revenue. • Residential customer late fees are now presented in other revenue. These fees were previously presented as a reduction to other operating costs and expenses. • Certain costs, including costs related to the fulfillment of contracts with customers, are now presented as other assets and the related costs are recognized over time in operating costs and expenses, which are comprised of total costs and expenses, excluding depreciation and amortization expense and other operating gains. These amounts were previously presented as intangible assets, and the expenses were previously presented in amortization expense. The payments related to these assets are now presented in net cash provided by operating activities rather than in cash paid for intangible assets in our consolidated statement of cash flows. Changes to the Timing of Recognition of Revenue and Related Costs • Revenue for upfront installation services that are not distinct and commission expenses are now recognized as revenue and operating costs and expenses, respectively, over a period of time rather than recognized immediately as they were previously. We recorded a deferred revenue liability related to upfront installation fees that are not distinct services, which required us to allocate the installation fees to the respective service. The installation fees are generally recognized as revenue over the period that the fee would influence a customer to renew their service. This period is less than a year for Cable Communications residential customers and the term of the related contract for business services customers. Incremental costs to obtain a contract with a customer, such as commissions for our business customers, are now deferred and recognized over the contract term. Sales commissions related to our Cable Communications residential customers are expensed as incurred as the related period of benefit is less than a year. The tables below present the effects these changes had on our Cable Communications segment revenue, operating costs and expenses, and depreciation and amortization expense as a result of the adoption of updated guidance for the prior year periods. Previously reported amounts are based on amounts previously presented in the segment information footnote. Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 14,769 $ 912 $ 15,681 Video 23,129 (255 ) 22,874 Voice 3,391 699 4,090 Business services 6,216 221 6,437 Advertising 2,257 193 2,450 Other 2,757 (1,219 ) 1,538 Total Cable Communications revenue $ 52,519 $ 551 $ 53,070 Operating costs and expenses $ 31,349 $ 653 $ 32,002 Depreciation and amortization expense $ 8,143 $ (137 ) $ 8,006 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 13,532 $ 889 $ 14,421 Video 22,357 (153 ) 22,204 Voice 3,540 619 4,159 Business services 5,514 191 5,705 Advertising 2,476 150 2,626 Other 2,629 (1,167 ) 1,462 Total Cable Communications revenue $ 50,048 $ 529 $ 50,577 Operating costs and expenses $ 29,939 $ 624 $ 30,563 Depreciation and amortization expense $ 7,670 $ (132 ) $ 7,538 NBCUniversal Segments The adoption of the updated guidance impacted the timing of recognition for some of our revenue contracts, primarily for content licensing agreements. As a result of the adoption of the updated guidance, when the term of an existing content licensing agreement is renewed or extended, revenue is not recognized until the date when the renewal or extension period begins. Under the prior guidance, revenue for the content licensing renewal period was recognized on the date that the renewal was agreed to contractually. This change resulted in delayed revenue recognition for content licensing renewals or extensions in our Cable Networks, Broadcast Television and Filmed Entertainment segments. This change also impacted the timing of the related amortization of our film and television costs and participations and residuals expenses. The adoption of the updated guidance did not have a material impact on the results of operations or financial position for the NBCUniversal segments. Financial Assets and Financial Liabilities In January 2016, the FASB updated the accounting guidance related to the recognition and measurement of financial assets and financial liabilities. The updated accounting guidance, among other things, requires that all nonconsolidated equity investments, except those accounted for under the equity method, be measured at fair value and the changes in fair value be recognized in net income. On January 1, 2018, we adopted the updated guidance prospectively along with a related clarifying update and as a result, we recorded an immaterial cumulative effect adjustment to retained earnings, accumulated other comprehensive income (loss) and investments. See Note 10 for additional information. Restricted Cash In November 2016, the FASB updated the accounting guidance related to restricted cash. The new standard requires that the statement of cash flows present the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents, and a reconciliation of that total to amounts presented on the balance sheet. We adopted the updated guidance on January 1, 2018 and as required applied the retrospective transition method. The adoption did not have a material impact for any period presented. Leases In February 2016, the FASB updated the accounting guidance related to leases. The updated accounting guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases with the exception of short-term leases. The asset and liability are initially measured based on the present value of committed lease payments. For a lessee, the recognition, measurement and presentation of expenses and cash flows arising from a lease do not significantly change from previous guidance. For a lessor, the accounting applied is also largely unchanged from previous guidance. We will adopt the updated accounting guidance in the first quarter of 2019 and prior periods will not be adjusted. We are currently in the process of determining the impact that the updated accounting will have on our consolidated financial statements. See Note 17 for a summary of our undiscounted minimum rental commitments under operating leases as of December 31, 2018.
NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Recent Accounting Pronouncements and Tax Reform	Note 8: Recent Accounting Pronouncements Revenue Recognition In May 2014, the Financial Accounting Standards Board (“FASB”) updated the accounting guidance related to revenue recognition. The updated accounting guidance provides a single, contract-based revenue recognition model to help improve financial reporting by providing clearer guidance on when an entity should recognize revenue and by reducing the number of standards to which an entity has to refer. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the updated guidance on January 1, 2018 on a full retrospective basis, which required us to reflect the impact of the updated guidance for all periods presented. The adoption of the new standard did not have a material impact on our consolidated results of operations or financial position for any period presented. The updated guidance also requires additional disclosures regarding the nature, timing and uncertainty of our revenue transactions. See Note 3 for additional information. The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 32,997 $ (47 ) $ 32,950 Total costs and expenses $ 26,516 $ (43 ) $ 26,473 Operating income $ 6,481 $ (4 ) $ 6,477 Net income attributable to NBCUniversal $ 5,084 $ (4 ) $ 5,080 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 31,593 $ (195 ) $ 31,398 Total costs and expenses $ 26,171 $ (131 ) $ 26,040 Operating income $ 5,422 $ (64 ) $ 5,358 Net income attributable to NBCUniversal $ 4,235 $ (64 ) $ 4,171 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 11,673 $ 284 $ 11,957 Film and television costs $ 7,071 $ 11 $ 7,082 Other noncurrent assets, net $ 1,872 $ (68 ) $ 1,804 Total assets $ 71,073 $ 227 $ 71,300 Total current liabilities $ 9,602 $ 330 $ 9,932 Other noncurrent liabilities $ 4,109 $ 44 $ 4,153 Total equity $ 43,188 $ (147 ) $ 43,041 Total liabilities and equity $ 71,073 $ 227 $ 71,300 The adoption of the updated guidance impacted the timing of recognition for some of our revenue contracts, primarily for content licensing agreements. As a result of the adoption of the updated guidance, when the term of an existing content licensing agreement is renewed or extended, revenue is not recognized until the date when the renewal or extension period begins. Under the prior guidance, revenue for the content licensing renewal period was recognized on the date that the renewal was agreed to contractually. This change resulted in delayed revenue recognition for content licensing renewals or extensions in our Cable Networks, Broadcast Television and Filmed Entertainment segments. This change also impacted the timing of the related amortization of our film and television costs and participations and residuals expenses. The adoption of the updated guidance did not have a material impact on the results of operations or financial position for the reportable segments. Financial Assets and Financial Liabilities In January 2016, the FASB updated the accounting guidance related to the recognition and measurement of financial assets and financial liabilities. The updated accounting guidance, among other things, requires that all nonconsolidated equity investments, except those accounted for under the equity method, be measured at fair value and the changes in fair value be recognized in net income. On January 1, 2018, we adopted the updated guidance prospectively along with a related clarifying update and as a result, we recorded a $232 million cumulative effect adjustment to member's capital and accumulated other comprehensive income (loss). See Note 9 for additional information. Restricted Cash In November 2016, the FASB updated the accounting guidance related to restricted cash. The new standard requires that the statement of cash flows present the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents, and a reconciliation of that total to amounts presented on the balance sheet. We adopted the updated guidance on January 1, 2018 and as required applied the retrospective transition method. The adoption did not have a material impact for any period presented. Leases In February 2016, the FASB updated the accounting guidance related to leases. The updated accounting guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases with the exception of short-term leases. The asset and liability are initially measured based on the present value of committed lease payments. For a lessee, the recognition, measurement and presentation of expenses and cash flows arising from a lease do not significantly change from previous guidance. For a lessor, the accounting applied is also largely unchanged from previous guidance. We will adopt the updated accounting guidance in the first quarter of 2019 and prior periods will not be adjusted. We are currently in the process of determining the impact that the updated accounting will have on our consolidated financial statements. See Note 14 for a summary of our undiscounted minimum rental commitments under operating leases as of December 31, 2018.

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments [Line Items]
Investments	Note 10: Investments December 31 (in millions) 2018 2017 Equity method $ 4,035 $ 3,546 Marketable equity securities 341 433 Nonmarketable equity securities 1,805 1,186 Other investments 1,796 1,785 Total investments 7,977 6,950 Less: Current investments 94 19 Noncurrent investments $ 7,883 $ 6,931 Investment and Other Income (Loss), Net Year ended December 31 (in millions) 2018 2017 2016 Equity in net income (losses) of investees, net $ (364 ) $ 107 $ (104 ) Realized and unrealized gains (losses) on equity securities, net (187 ) (17 ) 12 Other income (loss), net 326 331 529 Investment and other income (loss), net $ (225 ) $ 421 $ 437 Beginning January 1, 2018, in connection with our adoption of the updated accounting guidance related to the recognition and measurement of financial assets and financial liabilities (see Note 9), we updated the presentation and accounting policies for our investments previously classified as fair value and cost method investments. The investment categories presented in the table above are based on the new guidance and updated policies, where applicable, are described below. Equity Method We use the equity method to account for investments in which we have the ability to exercise significant influence over the investee’s operating and financial policies or in which we hold a significant partnership or limited liability company interest. Equity method investments are recorded at cost and are adjusted to recognize (1) our proportionate share of the investee’s net income or loss after the date of investment, (2) amortization of the recorded investment that exceeds our share of the book value of the investee’s net assets, (3) additional contributions made and dividends received, and (4) impairments resulting from other-than-temporary declines in fair value. For some investments, we record our share of the investee’s net income or loss one quarter in arrears due to the timing of our receipt of such information. Gains or losses on the sale of equity method investments are recorded to other income (loss), net. If an equity method investee were to issue additional securities that would change our proportionate share of the entity, we would recognize the change, if any, as a gain or loss to other income (loss), net. Atairos On January 1, 2016, we established Atairos Group, Inc., a strategic company focused on investing in and operating companies in a range of industries and business sectors, both domestically and internationally. Atairos has a term of up to 12 years and is controlled by management companies led by our former CFO through interests that carry all of the voting rights. We are the only investor other than our former CFO and the other management company employees. In February 2018, we amended our agreement with Atairos, which primarily increases our commitment to fund Atairos from up to $4 billion to up to $ 5 billion in the aggregate at any one time, subject to certain offsets. The amendment also increases our commitment to fund Atairos for a management fee from $40 million to $45 million annually, subject to certain annual adjustments. The management company investors have committed to fund from $50 million to $100 million , with at least $40 million to be funded by our former CFO, subject to his continued role with Atairos. Our economic interests do not carry voting rights and obligate us to absorb approximately 99% of any losses and they provide us the right to receive approximately 86% of any residual returns in Atairos, in either case on a cumulative basis. We have concluded that Atairos is a VIE, that we do not have the power to direct the activities that most significantly impact the economic performance of Atairos as we have no voting rights and only certain consent rights, and that we are not a related party with our former CFO or the management companies. We therefore do not consolidate Atairos and account for our investment as an equity method investment. There are no other liquidity arrangements, guarantees or other financial commitments between Comcast and Atairos, and therefore our maximum risk of financial loss is our investment balance and remaining unfunded capital commitment. As of December 31, 2018 and 2017 , our investment in Atairos was $ 2.7 billion and $ 2.4 billion , respectively. In 2018 , 2017 and 2016, we made cash capital contributions totaling $ 282 million , $994 million and $1.2 billion , respectively, to Atairos. Atairos follows investment company accounting and records its investments at their fair values each reporting period with the net gains or losses reflected in its statement of operations. We recognize our share of these gains and losses in equity in net income (losses) of investees, net. In 2018 , we recognized our share of Atairos’ losses of $ 31 million ; in 2017 and 2016, we recognized our share of Atairos’ income of $281 million and losses of $38 million respectively. In April 2018, we sold a controlling interest in our arena management-related businesses to Atairos and received as consideration additional equity interests in Atairos. In connection with the sale of the businesses, we recognized a pre-tax gain of $200 million in other operating gains. In July 2017, we sold a business to a company owned by Atairos and received as consideration an investment in that company. In connection with the sale of the business, we recognized a pre-tax gain of $105 million in other operating gains. We account for our retained ownership in the businesses as equity method investments. Hulu As of December 31, 2018 and 2017 , our investment in Hulu was $ 248 million and $ 249 million , respectively. In 2018, 2017 and 2016, we made cash capital contributions totaling $454 million , $300 million and $50 million , respectively, to Hulu. In 2018, 2017 and 2016, we recognized our proportionate share of Hulu’s losses of $454 million , $276 million and $168 million , respectively, in equity in net income (losses) of investees, net. In August 2016, Time Warner Inc. acquired a 10% interest in Hulu, which diluted our interest in Hulu from 33% to 30% . For a period not to exceed 3 years , Time Warner may put its shares to Hulu or Hulu may call Time Warner’s shares under certain limited circumstances arising from regulatory review. Given the contingent nature of the put and call options, we recorded a deferred gain of $159 million and a corresponding increase to our investment in Hulu as a result of the dilution. The deferred gain will be recognized in other income (loss), net if and when the options expire unexercised. The Weather Channel In March 2018, we sold our investment in The Weather Channel cable network and recognized a pretax gain of $64 million in other income (loss), net. In January 2016, following a legal restructuring at The Weather Channel, we and the other investors sold the entity holding The Weather Channel’s product and technology businesses to IBM. Following the close of the transaction, we continued to hold an investment in The Weather Channel cable network through a new holding company. As a result of the sale of our investment, we recognized a pretax gain of $108 million in other income (loss), net. Marketable Equity Securities We classify publicly traded investments with readily determinable fair values that are not accounted for under the equity method as marketable equity securities. Marketable equity securities are recorded at cost and adjusted to fair value at each reporting period. The changes in fair value between measurement dates are recorded in realized and unrealized gains (losses) on equity securities, net. The fair values of our marketable equity securities are based on Level 1 inputs that use quoted market prices. Snap In March 2017, we acquired an interest in Snap Inc. for $500 million as part of its initial public offering, which we have classified as a marketable equity security. Snap is a camera company whose primary product is Snapchat, a camera app that was created to help people communicate through short videos and images. As of December 31, 2018 and 2017 , our investment in Snap was $162 million and $ 430 million , respectively. In 2018 , we recognized unrealized losses of $ 268 million in realized and unrealized gains (losses) on equity securities, net related to our investment in Snap. Prior to the updated accounting guidance, unrealized gains and losses related to our investment in Snap were recorded to accumulated other comprehensive income. Nonmarketable Equity Securities We classify investments without readily determinable fair values that are not accounted for under the equity method as nonmarketable equity securities. The accounting guidance requires nonmarketable equity securities to be recorded at cost and adjusted to fair value at each reporting period. However, the guidance allows for a measurement alternative, which is to record the investments at cost, less impairment, if any, and subsequently adjust for observable price changes of identical or similar investments of the same issuer. We apply this measurement alternative to a majority of our nonmarketable equity securities. When an observable event occurs, we estimate the fair values of our nonmarketable equity securities based on Level 2 inputs that are derived from observable price changes of similar securities adjusted for insignificant differences in rights and obligations. The changes in value are recorded in realized and unrealized gains (losses) on equity securities, net. Other Investments AirTouch We hold two series of preferred stock of Verizon Americas, Inc., formerly known as AirTouch Communications, Inc., a subsidiary of Verizon Communications Inc., which are redeemable in April 2020. As of both December 31, 2018 and 2017 , our investment in AirTouch was $1.6 billion . We account for our investment in AirTouch as a held to maturity investment using the cost method. As of both December 31, 2018 and 2017 , the estimated fair value of the AirTouch preferred stock was $1.7 billion . The dividend and redemption activity of the AirTouch preferred stock determines the dividend and redemption payments associated with substantially all of the preferred shares issued by one of our consolidated subsidiaries, which is a VIE. The subsidiary has three series of preferred stock outstanding with an aggregate redemption value of $1.75 billion . Substantially all of the AirTouch preferred stock is redeemable in April 2020 at a redemption value of $1.65 billion . As of both December 31, 2018 and 2017 , the two series of redeemable subsidiary preferred shares were recorded at $1.6 billion , and those amounts are included in other noncurrent liabilities. As of both December 31, 2018 and 2017 , the liability related to the redeemable subsidiary preferred shares had an aggregate estimated fair value of $1.7 billion . The estimated fair values of the AirTouch preferred stock and redeemable subsidiary preferred shares are based on Level 2 inputs that use pricing models whose inputs are derived primarily from or corroborated by observable market data through correlation or other means for substantially the full term of the financial instrument. The one series of nonredeemable subsidiary preferred shares was recorded at $100 million as of both December 31, 2018 and 2017 , and those amounts are included in noncontrolling interests in our consolidated balance sheet. The carrying amount of the nonredeemable subsidiary preferred shares approximates its fair value. Impairment Testing of Investments We review our investment portfolio, other than our marketable equity securities, each reporting period to determine whether there are identified events or circumstances that would indicate there is a decline in the fair value. For our nonpublic investments, if there are no identified events or circumstances that would have a significant adverse effect on the fair value of the investment, then the fair value is not estimated. For our equity method investments and held to maturity investments, if an investment is deemed to have experienced an other-than-temporary decline below its cost basis, we reduce the carrying amount of the investment to its quoted or estimated fair value, as applicable, and establish a new cost basis for the investment. For our nonmarketable equity securities, we record the impairment to realized and unrealized gains (losses) on equity securities, net. For our equity method investments and our held to maturity investments, we record the impairment to other income (loss), net.
NBCUniversal Media LLC [Member]
Investments [Line Items]
Investments	Note 9: Investments December 31 (in millions) 2018 2017 Equity method $ 707 $ 690 Marketable equity securities 162 430 Nonmarketable equity securities 811 696 Total investments $ 1,680 $ 1,816 Investment and Other Income (Loss), Net Year ended December 31 (in millions) 2018 2017 2016 Equity in net income (losses) of investees, net $ (371 ) $ (201 ) $ (99 ) Realized and unrealized gains (losses) on equity securities, net (217 ) — 3 Other income (loss), net 67 57 120 Investment and other income (loss), net $ (521 ) $ (144 ) $ 24 Equity Method We use the equity method to account for investments in which we have the ability to exercise significant influence over the investee’s operating and financial policies or in which we hold a significant partnership or limited liability company interest. Equity method investments are recorded at cost and are adjusted to recognize (1) our proportionate share of the investee’s net income or loss after the date of investment, (2) amortization of the recorded investment that exceeds our share of the book value of the investee’s net assets, (3) additional contributions made and dividends received, and (4) impairments resulting from other-than-temporary declines in fair value. For some investments, we record our share of the investee’s net income or loss one quarter in arrears due to the timing of our receipt of such information. Gains or losses on the sale of equity method investments are recorded to other income (loss), net. If an equity method investee were to issue additional securities that would change our proportionate share of the entity, we would recognize the change, if any, as a gain or loss to other income (loss), net. Hulu As of December 31, 2018 and 2017 , our investment in Hulu was $248 million and $249 million , respectively. In 2018, 2017 and 2016, we made cash capital contributions totaling $454 million , $300 million and $50 million , respectively, to Hulu. In 2018, 2017 and 2016, we recognized our proportionate share of Hulu’s losses of $454 million , $276 million and $168 million , respectively, in equity in net income (losses) of investees, net. In August 2016, Time Warner Inc. acquired a 10% interest in Hulu, which diluted our interest in Hulu from 33% to 30% . For a period not to exceed 3 years , Time Warner may put its shares to Hulu or Hulu may call Time Warner’s shares under certain limited circumstances arising from regulatory review. Given the contingent nature of the put and call options, we recorded a deferred gain of $159 million and a corresponding increase to our investment in Hulu as a result of the dilution. The deferred gain will be recognized in other income (loss), net if and when the options expire unexercised. The Weather Channel In March 2018, we sold our investment in The Weather Channel cable network and recognized a pretax gain of $64 million in other income (loss), net. In January 2016, following a legal restructuring at The Weather Channel, we and the other investors sold the entity holding The Weather Channel’s product and technology businesses to IBM. Following the close of the transaction, we continued to hold an investment in The Weather Channel cable network through a new holding company. As a result of the sale of our investment, we recognized a pretax gain of $108 million in other income (loss), net. Marketable Equity Securities We classify publicly traded investments with readily determinable fair values that are not accounted for under the equity method as marketable equity securities. Marketable equity securities are recorded at cost and adjusted to fair value at each reporting period. The changes in fair value between measurement dates are recorded in realized and unrealized gains (losses) on equity securities, net. The fair values of our marketable equity securities are based on Level 1 inputs that use quoted market prices. Snap In March 2017, Comcast acquired an interest in Snap Inc. as part of its initial public offering. On March 31, 2017, Comcast contributed its investment in Snap to us as an equity contribution of $662 million , which was recorded in our consolidated statement of equity based on the fair value of the investment as of March 31, 2017. We have classified our investment as a marketable security. Snap is a camera company whose primary product is Snapchat, a camera app that was created to help people communicate through short videos and images. As of December 31, 2018 and 2017 , we had an investment in Snap of $ 162 million and $ 430 million , respectively. In 2018 , we recognized unrealized losses of $268 million in realized and unrealized gains (losses) on equity securities, net related to our investment in Snap. Prior to the updated accounting guidance, unrealized gains and losses related to our investment in Snap were recorded to accumulated other comprehensive income. Nonmarketable Equity Securities We classify investments without readily determinable fair values that are not accounted for under the equity method as nonmarketable equity securities. The accounting guidance requires nonmarketable equity securities to be recorded at cost and adjusted to fair value at each reporting period. However, the guidance allows for a measurement alternative, which is to record the investments at cost, less impairment, if any, and subsequently adjust for observable price changes of identical or similar investments of the same issuer. We apply this measurement alternative to our nonmarketable equity securities. When an observable event occurs, we estimate the fair values of our nonmarketable equity securities based on Level 2 inputs that are derived from observable price changes of similar securities adjusted for insignificant differences in rights and obligations. The changes in value are recorded in realized and unrealized gains (losses) on equity securities, net. Impairment Testing of Investments We review our investment portfolio, other than our marketable equity securities, each reporting period to determine whether there are identified events or circumstances that would indicate there is a decline in the fair value. For our nonpublic investments, if there are no identified events or circumstances that would have a significant adverse effect on the fair value of the investment, then the fair value is not estimated. For our equity method investments and held to maturity investments, if an investment is deemed to have experienced an other-than-temporary decline below its cost basis, we reduce the carrying amount of the investment to its quoted or estimated fair value, as applicable, and establish a new cost basis for the investment. For our nonmarketable equity securities, we record the impairment to realized and unrealized gains (losses) on equity securities, net. For our equity method investments and our held to maturity investments, we record the impairment to other income (loss), net.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and Equipment	Note 11: Property and Equipment December 31 (in millions) Weighted-Average 2018 2017 Cable distribution system 11 years $ 38,380 $ 36,046 Customer premise equipment 6 years 26,208 26,392 Other equipment 8 years 12,437 10,518 Buildings and leasehold improvements 30 years 14,188 12,346 Construction in process N/A 2,991 1,752 Land N/A 1,539 1,332 Property and equipment, at cost 95,743 88,386 Less: Accumulated depreciation 51,306 49,916 Property and equipment, net $ 44,437 $ 38,470 Property and equipment are stated at cost. We capitalize improvements that extend asset lives and expense repairs and maintenance costs as incurred. We record depreciation using the straight-line method over the asset’s estimated useful life. For assets that are sold or retired, we remove the applicable cost and accumulated depreciation and, unless the gain or loss on disposition is presented separately, we recognize it as a component of depreciation expense. In accordance with the accounting guidance related to cable television companies, our Cable Communications segment capitalizes the costs associated with the construction of and improvements to our cable transmission and distribution facilities, including scalable infrastructure and line extensions; costs associated with acquiring and deploying new customer premise equipment; and costs associated with installation of our services. Costs capitalized include all direct costs for labor and materials, as well as various indirect costs. Costs incurred in connection with subsequent disconnects and reconnects are expensed as they are incurred. We evaluate the recoverability of our property and equipment whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of depreciation expense.
NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	Note 10: Property and Equipment December 31 (in millions) Weighted-Average 2018 2017 Buildings and leasehold improvements 31 years $ 8,877 $ 8,124 Furniture, fixtures and equipment 11 years 5,501 4,843 Construction in process N/A 2,676 1,506 Land N/A 1,129 1,039 Property and equipment, at cost 18,183 15,512 Less: Accumulated depreciation 4,994 4,166 Property and equipment, net $ 13,189 $ 11,346 Property and equipment are stated at cost. We capitalize improvements that extend asset lives and expense repairs and maintenance costs as incurred. We record depreciation using the straight-line method over the asset’s estimated useful life. For assets that are sold or retired, we remove the applicable cost and accumulated depreciation and, unless the gain or loss on disposition is presented separately, we recognize it as a component of depreciation expense. We evaluate the recoverability of our property and equipment whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of depreciation expense.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets [Line Items]
Goodwill and Intangible Assets	Note 12: Goodwill and Intangible Assets Goodwill NBCUniversal (in millions) Cable Cable Broadcast Filmed Theme Sky Corporate Total Balance, December 31, 2016 $ 12,645 $ 13,183 $ 806 $ 2,993 $ 6,341 $ — $ 12 $ 35,980 Acquisitions 140 241 — 32 — — 5 418 Dispositions — — — — — — (11 ) (11 ) Adjustments (a) (1 ) 1 — 185 — — 1 186 Foreign currency translation — 2 — 2 203 — — 207 Balance, December 31, 2017 12,784 13,427 806 3,212 6,544 — 7 36,780 Acquisitions (b) — — 36 — — 29,889 — 29,925 Dispositions — — — (8 ) — — (5 ) (13 ) Adjustments — (13 ) 1 (9 ) — — — (21 ) Foreign currency translation — (7 ) — (11 ) 140 (639 ) — (517 ) Balance, December 31, 2018 $ 12,784 $ 13,407 $ 843 $ 3,184 $ 6,684 $ 29,250 $ 2 $ 66,154 (a) Adjustments in 2017 primarily included the updated allocation of the purchase price for DreamWorks Animation. (b) Acquisitions in 2018 primarily included the Sky acquisition. As of December 31, 2018, all goodwill resulting from the Sky acquisition has been presented in the Sky segment. Our evaluation of reporting units and assignment of goodwill resulting from the Sky acquisition are preliminary and subject to change. We will finalize the analysis no later than one year from the acquisition date. See Note 8 for further information on the Sky acquisition. Goodwill is calculated as the excess of the consideration transferred over the identifiable net assets acquired in a business combination and represents the future economic benefits expected to arise from anticipated synergies and intangible assets acquired that do not qualify for separate recognition, including assembled workforce, noncontractual relationships and other agreements. We assess the recoverability of our goodwill annually, or more frequently whenever events or substantive changes in circumstances indicate that the carrying amount of a reporting unit may exceed its fair value. We test goodwill for impairment at the reporting unit level. To determine our reporting units, we evaluate the components one level below the segment level and we aggregate the components if they have similar economic characteristics. As a result of this assessment, our reporting units are generally the same as our reportable segments. We evaluate the determination of our reporting units used to test for impairment periodically or whenever events or substantive changes in circumstances occur. The assessment of recoverability may first consider qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. The quantitative assessment considers whether the carrying amount of a reporting unit exceeds its fair value, in which case an impairment charge is recorded to the extent the reporting unit’s carrying value exceeds its fair value. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any impairment charges in any of the periods presented. Intangible Assets 2018 (a) 2017 December 31 (in millions) Weighted-Average Original Useful Life as of December 31, 2018 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Indefinite-Lived Intangible Assets: Franchise rights N/A $ 59,365 $ 59,364 Trade names N/A 9,633 2,981 FCC licenses N/A 2,333 2,238 Finite-Lived Intangible Assets: Customer relationships 16 years 25,046 $ (6,682 ) 13,612 $ (5,819 ) Software 5 years 11,395 (5,990 ) 8,258 (4,846 ) Patents and other technology rights 7 years 260 (234 ) 259 (221 ) Other agreements and rights 18 years 3,885 (1,288 ) 2,736 (1,065 ) Total $ 111,917 $ (14,194 ) $ 89,448 $ (11,951 ) (a) In 2018, we recorded intangible assets in connection with the Sky acquisition, which primarily consisted of customer relationships and trade names (see Note 8 for additional information). Indefinite-Lived Intangible Assets Indefinite-lived intangible assets consist primarily of our cable franchise rights. Our cable franchise rights represent the values we attributed to agreements with state and local authorities that allow access to homes and businesses in cable service areas acquired in business combinations. We do not amortize our cable franchise rights because we have determined that they meet the definition of indefinite-lived intangible assets since there are no legal, regulatory, contractual, competitive, economic or other factors which limit the period over which these rights will contribute to our cash flows. We reassess this determination periodically or whenever events or substantive changes in circumstances occur. We assess the recoverability of our cable franchise rights and other indefinite-lived intangible assets annually, or more frequently whenever events or substantive changes in circumstances indicate that the assets might be impaired. Our three Cable Communications divisions represent the unit of account we use to test for impairment of our cable franchise rights. We evaluate the unit of account used to test for impairment of our cable franchise rights and other indefinite-lived intangible assets periodically or whenever events or substantive changes in circumstances occur to ensure impairment testing is performed at an appropriate level. The assessment of recoverability may first consider qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. When performing a quantitative assessment, we estimate the fair value of our cable franchise rights and other indefinite-lived intangible assets primarily based on a discounted cash flow analysis that involves significant judgment. When analyzing the fair values indicated under the discounted cash flow models, we also consider multiples of Adjusted EBITDA generated by the underlying assets, current market transactions and profitability information. If the fair value of our cable franchise rights or other indefinite-lived intangible assets were less than the carrying amount, we would recognize an impairment charge for the difference between the estimated fair value and the carrying value of the assets. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any material impairment charges in any of the periods presented. Finite-Lived Intangible Assets Estimated Amortization Expense of Finite-Lived Intangible Assets (in millions) 2019 $ 3,719 2020 $ 3,490 2021 $ 3,104 2022 $ 2,689 2023 $ 2,260 Finite-lived intangible assets are subject to amortization and consist primarily of customer relationships acquired in business combinations, software, and intellectual property rights. Our finite-lived intangible assets are amortized primarily on a straight-line basis over their estimated useful life or the term of the associated agreement. We capitalize direct development costs associated with internal-use software, including external direct costs of material and services and payroll costs for employees devoting time to these software projects. We also capitalize costs associated with the purchase of software licenses. We generally amortize them on a straight-line basis over a period not to exceed five years . We expense maintenance and training costs, as well as costs incurred during the preliminary stage of a project, as they are incurred. We capitalize initial operating system software costs and amortize them over the life of the associated hardware. We evaluate the recoverability of our finite-lived intangible assets whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of amortization expense.
NBCUniversal Media LLC [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill and Intangible Assets	Note 11: Goodwill and Intangible Assets Goodwill (in millions) Cable Broadcast Filmed Theme Total Balance, December 31, 2016 $ 13,183 $ 806 $ 2,993 $ 6,341 $ 23,323 Acquisitions 241 — 32 — 273 Adjustments (a) 1 — 185 — 186 Foreign currency translation 2 — 2 203 207 Balance, December 31, 2017 13,427 806 3,212 6,544 23,989 Acquisitions — 36 — — 36 Dispositions — — (8 ) — (8 ) Adjustments (13 ) 1 (9 ) — (21 ) Foreign currency translation (7 ) — (11 ) 140 122 Balance, December 31, 2018 $ 13,407 $ 843 $ 3,184 $ 6,684 $ 24,118 (a) Adjustments in 2017 primarily included the updated allocation of the purchase price for DreamWorks Animation. Goodwill is calculated as the excess of the consideration transferred over the identifiable net assets acquired in a business combination and represents the future economic benefits expected to arise from anticipated synergies and intangible assets acquired that do not qualify for separate recognition, including assembled workforce, noncontractual relationships and other agreements. We assess the recoverability of our goodwill annually, or more frequently whenever events or substantive changes in circumstances indicate that the carrying amount of a reporting unit may exceed its fair value. We test goodwill for impairment at the reporting unit level. To determine our reporting units, we evaluate the components one level below the segment level and we aggregate the components if they have similar economic characteristics. As a result of this assessment, our reporting units are generally the same as our four reportable segments. We evaluate the determination of our reporting units used to test for impairment periodically or whenever events or substantive changes in circumstances occur. The assessment of recoverability may first consider qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. The quantitative assessment considers whether the carrying amount of a reporting unit exceeds its fair value, in which case an impairment charge is recorded to the extent the reporting unit’s carrying value exceeds its fair value. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any impairment charges in any of the periods presented. Intangible Assets 2018 2017 December 31 (in millions) Weighted-Average Gross Accumulated Gross Accumulated Finite-Lived Intangible Assets: Customer relationships 19 years $ 13,269 $ (6,283 ) $ 13,301 $ (5,643 ) Software 5 years 1,779 (932 ) 1,516 (737 ) Other 19 years 3,619 (1,375 ) 2,580 (1,205 ) Indefinite-Lived Intangible Assets: Trade names N/A 2,981 2,981 FCC licenses N/A 608 513 Total $ 22,256 $ (8,590 ) $ 20,891 $ (7,585 ) Indefinite-Lived Intangible Assets Indefinite-lived intangible assets consist of trade names and FCC licenses. We assess the recoverability of our indefinite-lived intangible assets annually, or more frequently whenever events or substantive changes in circumstances indicate that the assets might be impaired. We evaluate the unit of account used to test for impairment of our indefinite-lived intangible assets periodically or whenever events or substantive changes in circumstances occur to ensure impairment testing is performed at an appropriate level. The assessment of recoverability may first consider qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. When performing a quantitative assessment, we estimate the fair value of our indefinite-lived intangible assets primarily based on a discounted cash flow analysis that involves significant judgment. When analyzing the fair values indicated under the discounted cash flow models, we also consider multiples of Adjusted EBITDA generated by the underlying assets, current market transactions and profitability information. If the fair value of our indefinite-lived intangible assets were less than the carrying amount, we would recognize an impairment charge for the difference between the estimated fair value and the carrying value of the assets. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any material impairment charges in any of the periods presented. Finite-Lived Intangible Assets Estimated Amortization Expense of Finite-Lived Intangible Assets (in millions) 2019 $ 1,059 2020 $ 1,039 2021 $ 936 2022 $ 861 2023 $ 839 Finite-lived intangible assets are subject to amortization and consist primarily of customer relationships acquired in business combinations, software, and intellectual property rights. Our finite-lived intangible assets are amortized primarily on a straight-line basis over their estimated useful life or the term of the associated agreement. We capitalize direct development costs associated with internal-use software, including external direct costs of material and services and payroll costs for employees devoting time to these software projects. We also capitalize costs associated with the purchase of software licenses. We generally amortize them on a straight-line basis over a period not to exceed five years . We expense maintenance and training costs, as well as costs incurred during the preliminary stage of a project, as they are incurred. We capitalize initial operating system software costs and amortize them over the life of the associated hardware. We evaluate the recoverability of our finite-lived intangible assets whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of amortization expense.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee Benefit Plans	Note 13: Employee Benefit Plans Deferred Compensation Plans Year ended December 31 (in millions) 2018 2017 2016 Benefit obligation $ 2,885 $ 2,539 $ 2,164 Interest expense $ 222 $ 209 $ 178 We maintain unfunded, nonqualified deferred compensation plans for certain members of management and nonemployee directors. The amount of compensation deferred by each participant is based on participant elections. Participant accounts, except for those in the NBCUniversal plan, are credited with income primarily based on a fixed annual rate. Participants in the NBCUniversal plan designate one or more valuation funds, independently established funds or indices that are used to determine the amount of investment gain or loss in the participant’s account. Participants are eligible to receive distributions from their account based on elected deferral periods that are consistent with the plans and applicable tax law. We have purchased life insurance policies to recover a portion of the future payments related to our deferred compensation plans. As of December 31, 2018 and 2017 , the cash surrender value of these policies, which is recorded to other noncurrent assets, was $351 million and $820 million , respectively. Postretirement Benefit Plan Year ended December 31 (in millions) 2018 2017 Benefit obligation $ 408 $ 425 Amounts in accumulated other comprehensive income not yet recognized in benefits expense $ (439 ) $ (458 ) We sponsor a retiree health and welfare benefit plan that provides postretirement benefits to eligible employees. The plan provides, to eligible employees who retire from Comcast or its subsidiaries, an annual stipend for reimbursement of certain eligible healthcare costs. The amount of the stipend for an eligible retiree is fixed at a predetermined amount based on the retiree’s years of service and whether the retiree is eligible for Medicare. In December 2016, the plan was amended primarily to reduce the stipend benefits of active employees of Comcast and subsidiaries other than NBCUniversal who retire after December 31, 2017, and in 2017 additional amendments were made to reduce the benefits of NBCUniversal employees who retire after December 31, 2017. Additionally, under the plan, a small number of employees are also eligible to participate in legacy plan benefits that were previously sponsored by acquired companies. The plan is unfunded and substantially all of our postretirement benefit obligations are recorded to noncurrent liabilities. The expense we recognize for the plan is determined using certain assumptions, including the discount rate. The benefits expense we recognized for the plan was not material in any of the periods presented. Pension Plans NBCUniversal sponsors various nonqualified defined benefit pension plans for domestic employees. Since the future benefits have been frozen since the beginning of 2013, we did not recognize service costs related to the pension plans for any period presented. The benefits expense we recognized for our defined benefit plans was not material in any of the periods presented. In addition to the defined benefit plans it sponsors, NBCUniversal is also obligated to reimburse The General Electric Company (“GE”) for future benefit payments to those participants who were vested in the supplemental pension plan sponsored by GE at the time of the NBCUniversal transaction in 2011. These pension plans are currently unfunded and we recorded a benefit obligation of $312 million and $338 million as of December 31, 2018 and 2017 , respectively, which consists primarily of our obligations to reimburse GE. Retirement Investment Plans We sponsor several 401(k) defined contribution retirement plans that allow eligible employees to contribute a portion of their compensation through payroll deductions in accordance with specified plan guidelines. We make contributions to the plans that include matching a percentage of the employees’ contributions up to certain limits. In 2018 , 2017 and 2016 , expenses related to these plans totaled $546 million , $458 million and $446 million , respectively. Multiemployer Benefit Plans We participate in various multiemployer benefit plans, including pension and postretirement benefit plans, that cover some of our employees and temporary employees who are represented by labor unions. We also participate in other multiemployer benefit plans that provide health and welfare and retirement savings benefits to active and retired participants. We make periodic contributions to these plans in accordance with the terms of applicable collective bargaining agreements and laws but do not sponsor or administer these plans. We do not participate in any multiemployer benefit plans for which we consider our contributions to be individually significant. In 2018 , 2017 and 2016 , the total contributions we made to multiemployer pension plans were $102 million , $97 million and $84 million , respectively. In 2018 , 2017 and 2016 , the total contributions we made to multiemployer postretirement and other benefit plans were $183 million , $152 million and $136 million , respectively. If we cease to be obligated to make contributions or were to otherwise withdraw from participation in any of these plans, applicable law would require us to fund our allocable share of the unfunded vested benefits, which is known as a withdrawal liability. In addition, actions taken by other participating employers may lead to adverse changes in the financial condition of one of these plans, which could result in an increase in our withdrawal liability. Severance Benefits We provide severance benefits to certain former employees. A liability is recorded when payment is probable, the amount is reasonably estimable, and the obligation relates to rights that have vested or accumulated. In 2018 , 2017 and 2016 , we recorded severance costs of $243 million , $203 million and $315 million , respectively. Severance costs in 2016 included $61 million of severance costs associated with the acquisition of DreamWorks Animation.
NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee Benefit Plans	Note 12: Employee Benefit Plans Deferred Compensation Plans Year ended December 31 (in millions) 2018 2017 2016 Benefit obligation $ 719 $ 621 $ 494 Interest expense $ 58 $ 64 $ 48 Certain members of management participate in Comcast’s unfunded, nonqualified deferred compensation plan. The amount of compensation deferred by each participant is based on participant elections. Participant accounts are credited with income primarily based on a fixed annual rate. Additionally, we maintain unfunded, nonqualified deferred compensation plans for certain members of management. The amount of compensation deferred by each participant is based on participant elections. Participants designate one or more valuation funds, independently established funds or indices that are used to determine the amount of investment gain or loss in the participant’s account. Deferred compensation plan participants are eligible to receive distributions from their account based on elected deferral periods that are consistent with the plans and applicable tax law. Postretirement Benefit Plan Year ended December 31 (in millions) 2018 2017 Benefit obligation $ 47 $ 51 Amounts in accumulated other comprehensive income not yet recognized in benefits expense $ (163 ) $ (177 ) We provide postretirement benefits to eligible employees through a retiree health and welfare benefits plan. The plan provides credit to employees for length of service provided before Comcast’s acquisition of NBCUniversal. The plan provides eligible employees who retire from NBCUniversal with an annual stipend for reimbursement of certain eligible healthcare costs. The amount of the stipend for an eligible retiree is fixed at a predetermined amount based on the retiree’s years of service and whether the retiree is eligible for Medicare. In 2017, the plan was amended primarily to reduce the benefits of active employees who retire after December 31, 2017. The plan is unfunded and substantially all of our postretirement benefit obligations are recorded to noncurrent liabilities. The expense we recognize for the plan is determined using certain assumptions, including the discount rate. The benefits expense we recognized for the plan was not material in any of the periods presented. Pension Plans We sponsor various nonqualified defined benefit pension plans for domestic employees. Since the future benefits have been frozen since the beginning of 2013, we did not recognize service costs related to our pension plans in any of the periods presented. The benefits expense we recognized for our defined benefit plans was not material for any period presented. In addition to the defined benefit plans we sponsor, we are also obligated to reimburse The General Electric Company (“GE”) for future benefit payments to those participants who were vested in the supplemental pension plan sponsored by GE at the time of Comcast’s acquisition of NBCUniversal. These pension plans are currently unfunded and we recorded a benefit obligation of $312 million and $338 million as of December 31, 2018 and 2017 , respectively, which consists primarily of our obligations to reimburse GE. Retirement Investment Plans We sponsor several defined contribution retirement plans, including 401(k) plans, that allow eligible employees to contribute a portion of their compensation through payroll deductions in accordance with specified plan guidelines. We make contributions to the plans that include matching a percentage of the employees’ contributions up to certain limits. In 2018 , 2017 and 2016 , expenses related to these plans totaled $213 million , $201 million and $185 million , respectively. Multiemployer Benefit Plans We participate in various multiemployer benefit plans, including pension and postretirement benefit plans, that cover some of our employees and temporary employees who are represented by labor unions. We also participate in other multiemployer benefit plans that provide health and welfare and retirement savings benefits to active and retired participants. We make periodic contributions to these plans in accordance with the terms of applicable collective bargaining agreements and laws but do not sponsor or administer these plans. We do not participate in any multiemployer benefit plans for which we consider our contributions to be individually significant. In 2018 , 2017 and 2016 , the total contributions we made to multiemployer pension plans were $102 million , $97 million and $84 million , respectively. In 2018 , 2017 and 2016 , the total contributions we made to multiemployer postretirement and other benefit plans were $183 million , $152 million and $136 million , respectively. If we cease to be obligated to make contributions or were to otherwise withdraw from participation in any of these plans, applicable law would require us to fund our allocable share of the unfunded vested benefits, which is known as a withdrawal liability. In addition, actions taken by other participating employers may lead to adverse changes in the financial condition of one of these plans, which could result in an increase in our withdrawal liability. Severance Benefits We provide severance benefits to certain former employees. A liability is recorded when payment is probable, the amount is reasonably estimable, and the obligation relates to rights that have vested or accumulated. In 2018 , 2017 and 2016 , we recorded severance costs of $146 million , $108 million and $165 million , respectively. Severance costs in 2016 included $61 million of severance costs associated with the acquisition of DreamWorks Animation.

Equity

Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Equity	Note 14: Equity Common Stock In the aggregate, holders of our Class A common stock have 66 2 / 3 % of the voting power of our common stock and holders of our Class B common stock have 33 1 / 3 % of the voting power of our common stock, which percentage is generally non-dilutable under the terms of our articles of incorporation. Each share of our Class B common stock is entitled to 15 votes. The number of votes held by each share of our Class A common stock depends on the number of shares of Class A and Class B common stock outstanding at any given time. The 33 1 / 3 % aggregate voting power of our Class B common stock cannot be diluted by additional issuances of any other class of common stock. Our Class B common stock is convertible, share for share, into Class A common stock, subject to certain restrictions. Shares of Common Stock Outstanding (in millions) A B Balance, December 31, 2015 4,875 9 Stock compensation plans 23 — Repurchases and retirements of common stock (161 ) — Employee stock purchase plans 5 — Balance, December 31, 2016 4,742 9 Stock compensation plans 19 — Repurchases and retirements of common stock (131 ) — Employee stock purchase plans 5 — Balance, December 31, 2017 4,635 9 Stock compensation plans 15 — Repurchases and retirements of common stock (140 ) — Employee stock purchase plans 7 — Balance, December 31, 2018 4,517 9 Share Repurchases Effective January 1, 2017, our Board of Directors increased our share repurchase program authorization to a total of $12.0 billion , which does not have an expiration date. As of December 31, 2018, $2.0 billion remained under this authorization. Share Repurchases Under Share Repurchase Program Authorization Year ended December 31 (in millions) 2018 2017 2016 Cash consideration $ 5,000 $ 5,000 $ 5,000 Shares repurchased 140 131 161 Accumulated Other Comprehensive Income (Loss) December 31 (in millions) 2018 2017 Unrealized gains (losses) on marketable securities $ 3 $ (43 ) Deferred gains (losses) on cash flow hedges 55 9 Unrecognized gains (losses) on employee benefit obligations 325 260 Cumulative translation adjustments (751 ) 153 Accumulated other comprehensive income (loss), net of deferred taxes $ (368 ) $ 379

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Note 15: Share-Based Compensation The tables below provide information on our share-based compensation. Recognized Share-Based Compensation Expense Year ended December 31 (in millions) 2018 2017 2016 Restricted share units $ 402 $ 349 $ 306 Stock options 205 205 173 Employee stock purchase plans 32 32 28 Total $ 639 $ 586 $ 507 Our share-based compensation plans consist primarily of awards of RSUs and stock options to certain employees and directors as part of our approach to long-term incentive compensation. Awards generally vest over a period of 5 years and in the case of stock options, have a 10 year term. Additionally, through our employee stock purchase plans, employees are able to purchase shares of our common stock at a discount through payroll deductions. As of December 31, 2018 , all of our stock options outstanding were net settled stock options. Net settled stock options, as opposed to stock options exercised with a cash payment, result in fewer shares being issued and no cash proceeds being received by us when the options are exercised. In connection with the acquisition of Sky in the fourth quarter of 2018, Comcast issued replacement share-based compensation awards for non-vested awards based in Sky shares that were held by Sky employees at the time of the acquisition. The replacement awards included 8 million RSUs with a grant date weighted average fair value of $35.38 per RSU that will vest in 2020 and 2021. Stock Options and Restricted Share Units As of December 31, 2018, unless otherwise stated (in millions, except per share data) Stock Options RSUs Awards granted during 2018 41 24 Weighted-average exercise price of awards granted during 2018 $ 35.81 Stock options outstanding and nonvested RSUs 200 51 Weighted-average exercise price of stock options outstanding $ 27.69 Weighted-average fair value at grant date of nonvested RSUs $ 33.77 The cost associated with our share-based compensation is based on an award’s estimated fair value at the date of grant and is recognized over the period in which any related services are provided. RSUs are valued based on the closing price of our common stock on the date of grant and are discounted for the lack of dividends, if any, during the vesting period. We use the Black-Scholes option pricing model to estimate the fair value of stock option awards. The table below presents the weighted-average fair value on the date of grant of RSUs and stock options awarded under our various plans and the related weighted-average valuation assumptions. Year ended December 31 2018 2017 2016 RSUs fair value $ 35.56 $ 37.77 $ 30.02 Stock options fair value $ 7.14 $ 7.01 $ 5.78 Stock Option Valuation Assumptions: Dividend yield 2.1 % 1.7 % 1.8 % Expected volatility 22.0 % 20.1 % 23.0 % Risk-free interest rate 2.7 % 2.2 % 1.5 % Expected option life (in years) 6.0 6.1 6.1 As of December 31, 2018 , we had unrecognized pretax compensation expense of $1.1 billion related to nonvested RSUs and unrecognized pretax compensation expense of $437 million related to nonvested stock options that will be recognized over a weighted-average period of approximately 1.6 years and 1.7 years , respectively. In 2018 and 2017, we recognized $75 million and $297 million , respectively, as a reduction to income tax expense as a result of excess tax benefits associated with our share-based compensation plans. In 2016 , under prior accounting guidance, we recorded an increase to additional paid-in capital of $233 million as a result of excess tax benefits associated with our share-based compensation plans.

Supplemental Financial Informat

Supplemental Financial Information	12 Months Ended
	Dec. 31, 2018
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Note 16: Supplemental Financial Information Cash Payments for Interest and Income Taxes Year ended December 31 (in millions) 2018 2017 2016 Interest $ 2,897 $ 2,820 $ 2,565 Income taxes $ 2,355 $ 4,057 $ 3,693 Noncash Investing and Financing Activities During 2018 : • we acquired $2.1 billion of property and equipment and intangible assets that were accrued but unpaid • we recorded a liability of $860 million for a quarterly cash dividend of $0.19 per common share paid in January 2019 • we received noncash contributions from noncontrolling interests totaling $391 million related to Universal Beijing Resort (see Note 8) During 2017 : • we acquired $1.2 billion of property and equipment and intangible assets that were accrued but unpaid • we recorded a liability of $732 million for a quarterly cash dividend of $0.1575 per common share paid in January 2018 • we completed a senior notes exchange in the fourth quarter of 2017 in which we issued $5.5 billion aggregate principal amount of new senior notes in exchange for $3.9 billion aggregate principal amount of certain series of outstanding senior notes that were issued by us and NBCUniversal During 2016 : • we acquired $1.3 billion of property and equipment and intangible assets that were accrued but unpaid • we recorded a liability of $653 million for a quarterly cash dividend of $0.1375 per common share paid in January 2017 • we recorded a liability of $447 million for capital contributions to Atairos that were accrued in December and paid in January 2017 (see Note 10) Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheet to the total of the amounts reported in our consolidated statement of cash flows. December 31 (in millions) 2018 2017 Cash and cash equivalents $ 3,814 $ 3,428 Restricted cash included in other current assets 46 60 Restricted cash included in other noncurrent assets, net 49 83 Cash, cash equivalents and restricted cash, end of year $ 3,909 $ 3,571
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Note 13: Supplemental Financial Information Cash Payments for Interest and Income Taxes Year ended December 31 (in millions) 2018 2017 2016 Interest $ 408 $ 517 $ 548 Income taxes $ 430 $ 282 $ 208 Noncash Investing and Financing Activities During 2018 : • we acquired $1.4 billion of property and equipment and intangible assets that were accrued but unpaid • we received noncash contributions from noncontrolling interests totaling $391 million related to Universal Beijing Resort (see Note 7) During 2017 : • we acquired $325 million of property and equipment and intangible assets that were accrued but unpaid • Comcast contributed its investment in Snap to us at its fair value, which was a noncash transaction (see Note 9) • we and Comcast completed a senior notes exchange in the fourth quarter of 2017 (see Note 15) During 2016 : • we acquired $189 million of property and equipment and intangible assets that were accrued but unpaid • Comcast contributed the net assets of DreamWorks Animation to us, which was primarily a noncash transaction (see Note 7) Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheet to the total of the amounts reported in our consolidated statement of cash flows. December 31 (in millions) 2018 2017 Cash and cash equivalents $ 1,444 $ 2,347 Restricted cash included in other noncurrent assets, net 20 30 Cash, cash equivalents and restricted cash, end of year $ 1,464 $ 2,377 Accumulated Other Comprehensive Income (Loss) December 31 (in millions) 2018 2017 Unrealized gains (losses) on marketable securities $ — $ (233 ) Deferred gains (losses) on cash flow hedges 12 10 Unrecognized gains (losses) on employee benefit obligations 140 126 Cumulative translation adjustments 102 77 Accumulated other comprehensive income (loss) $ 254 $ (20 )

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitment And Contingencies [Line Items]
Commitments and Contingencies	Note 17: Commitments and Contingencies Commitments NBCUniversal and Sky enter into long-term commitments with third parties in the ordinary course of its business, including commitments to acquire film and television programming, obligations under various creative talent agreements, and various other television-related commitments. Some of NBCUniversal’s employees, including writers, directors, actors, technical and production personnel, and others, as well as some of its on-air and creative talent, are covered by collective bargaining agreements or works councils. As of December 31, 2018 , the total number of NBCUniversal employees covered by collective bargaining agreements was 10,000 full-time equivalent employees. Approximately 46% of these full-time equivalent employees were covered by collective bargaining agreements that have expired or are scheduled to expire during 2019 . We, through Comcast Spectacor, have employment agreements with both players and coaches of the Philadelphia Flyers. Certain of these employment agreements, which provide for payments that are guaranteed regardless of employee injury or termination, are covered by disability insurance if certain conditions are met. The table below summarizes our minimum annual programming and talent commitments and our minimum annual rental commitments under operating leases for office space, equipment and transponder service agreements. Programming and talent commitments include acquired film and television programming, including broadcast rights to sporting events, such as the Olympics, and other programming commitments, as well as various contracts with creative talent. As of December 31, 2018 (in millions) Programming and Talent Commitments Operating Leases 2019 $ 11,741 $ 759 2020 $ 10,468 $ 709 2021 $ 8,865 $ 616 2022 $ 5,193 $ 480 2023 $ 3,060 $ 414 Thereafter $ 17,142 $ 2,285 The table below presents our rental expense charged to operations. Year ended December 31 (in millions) 2018 2017 2016 Rental expense $ 779 $ 839 $ 744 Contractual Obligation We are party to a contractual obligation that involves an interest held by a third party in the revenue of certain theme parks. The arrangement provides the counterparty with the right to periodic payments associated with current period revenue which are recorded as an operating expense, and beginning in June 2017, the option to require NBCUniversal to purchase the interest for cash in an amount based on a contractual formula. The contractual formula is based on an average of specified historical theme park revenue at the time of exercise, which amount could be significantly higher than our carrying value. As of December 31, 2018 , our carrying value was $1.1 billion , and the value of the contractual obligation was $1.6 billion based on inputs to the contractual formula as of that date. Redeemable Subsidiary Preferred Stock NBCUniversal Enterprise is a holding company that we control and consolidate whose principal assets are its interests in NBCUniversal Holdings. The holders of the Series A cumulative preferred stock of NBCUniversal Enterprise have the right to cause NBCUniversal Enterprise to redeem their shares at a price equal to the $725 million aggregate liquidation preference plus accrued but unpaid dividends for a 30 day period beginning on March 19, 2020 and thereafter on every third anniversary of such date (each such date, a “put date”). The NBCUniversal Enterprise preferred stock pays dividends at a fixed rate of 5.25% per year. Shares of preferred stock can be called for redemption by NBCUniversal Enterprise at a price equal to the liquidation preference plus accrued but unpaid dividends one year following the put date applicable to such shares. Because certain of these redemption provisions are outside of our control, the NBCUniversal Enterprise preferred stock is presented outside of equity under the caption “redeemable noncontrolling interests and redeemable subsidiary preferred stock” in our consolidated balance sheet. Its initial value was based on the liquidation preference of the preferred stock and is adjusted for accrued but unpaid dividends. As of December 31, 2018 and 2017 , the fair value of the NBCUniversal Enterprise redeemable subsidiary preferred stock was $741 million and $748 million , respectively. The estimated fair values are based on Level 2 inputs that use pricing models whose inputs are derived primarily from or corroborated by observable market data through correlation or other means for substantially the full term of the financial instrument. Contingencies We are a defendant in several unrelated lawsuits claiming infringement of various patents relating to various aspects of our businesses. In certain of these cases other industry participants are also defendants, and also in certain of these cases we expect that any potential liability would be in part or in whole the responsibility of our equipment and technology vendors under applicable contractual indemnification provisions. In addition, we are subject to other legal proceedings and claims that arise in the ordinary course of our business. While the amount of ultimate liability with respect to such actions is not expected to materially affect our results of operations, cash flows or financial position, any litigation resulting from any such legal proceedings or claims could be time-consuming and injure our reputation.
NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Commitments and Contingencies	Note 14: Commitments and Contingencies Commitments We enter into long-term commitments with third parties in the ordinary course of our business, including commitments to acquire film and television programming, obligations under various creative talent agreements, and various other television-related commitments. Some of our employees, including writers, directors, actors, technical and production personnel, and others, as well as some of our on-air and creative talent, are covered by collective bargaining agreements or works councils. As of December 31, 2018 , the total number of employees covered by collective bargaining agreements was 10,000 full-time equivalent employees. Approximately 46% of these full-time equivalent employees were covered by collective bargaining agreements that have expired or are scheduled to expire during 2019 . The table below summarizes our minimum annual programming and talent commitments and our minimum annual rental commitments under operating leases for office space and equipment. Programming and talent commitments include acquired film and television programming, including broadcast rights to sporting events, such as the Olympics, and other programming commitments, as well as various contracts with creative talent. As of December 31, 2018 (in millions) Programming and Talent Commitments Operating Leases 2019 $ 5,371 $ 248 2020 $ 5,524 $ 232 2021 $ 3,922 $ 199 2022 $ 4,314 $ 168 2023 $ 2,181 $ 144 Thereafter $ 16,549 $ 1,380 The table below presents our rental expense charged to operations. Year ended December 31 (in millions) 2018 2017 2016 Rental expense $ 286 $ 274 $ 259 Contractual Obligation We are party to a contractual obligation that involves an interest held by a third party in the revenue of certain theme parks. The arrangement provides the counterparty with the right to periodic payments associated with current period revenue which are recorded as an operating expense, and beginning in June 2017, the option to require NBCUniversal to purchase the interest for cash in an amount based on a contractual formula. The contractual formula is based on an average of specified historical theme park revenue at the time of exercise, which amount could be significantly higher than our carrying value. As of December 31, 2018 , our carrying value was $1.1 billion , and the estimated value of the contractual obligation was $1.6 billion based on inputs to the contractual formula as of that date.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Note 18: Quarterly Financial Information (Unaudited) (in millions, except per share data) First Second Third Fourth Total 2018 Revenue $ 22,791 $ 21,735 $ 22,135 $ 27,846 $ 94,507 Operating income $ 4,645 $ 5,014 $ 4,836 $ 4,514 $ 19,009 Net income attributable to Comcast Corporation $ 3,118 $ 3,216 $ 2,886 $ 2,511 $ 11,731 Basic earnings per common share attributable to Comcast Corporation shareholders $ 0.67 $ 0.70 $ 0.63 $ 0.55 $ 2.56 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 0.66 $ 0.69 $ 0.62 $ 0.55 $ 2.53 Dividends declared per common share $ 0.19 $ 0.19 $ 0.19 $ 0.19 $ 0.76 2017 Revenue $ 20,587 $ 21,286 $ 21,081 $ 22,075 $ 85,029 Operating income $ 4,542 $ 4,568 $ 4,779 $ 4,129 $ 18,018 Net income attributable to Comcast Corporation (a) $ 2,573 $ 2,521 $ 2,642 $ 14,999 $ 22,735 Basic earnings per common share attributable to Comcast Corporation shareholders $ 0.54 $ 0.53 $ 0.56 $ 3.22 $ 4.83 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 0.53 $ 0.52 $ 0.55 $ 3.17 $ 4.75 Dividends declared per common share $ 0.1575 $ 0.1575 $ 0.1575 $ 0.1575 $ 0.63 Minor differences may exist due to rounding. (a) In the fourth quarter of 2017, net income attributable to Comcast Corporation included a $12.7 billion net income tax benefit as a result of the impacts of the 2017 tax reform legislation. See Note 5 for additional information.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Note 19: Condensed Consolidating Financial Information Comcast (“Comcast Parent”), Comcast Cable Communications, LLC (“CCCL Parent”) and NBCUniversal (“NBCUniversal Media Parent”) have fully and unconditionally guaranteed each other’s debt. See Note 7 for additional information on the cross-guarantee structure. Condensed Consolidating Statement of Income For the Year Ended December 31, 2018 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 94,507 $ — $ 94,507 Management fee revenue 1,197 — 1,175 — — (2,372 ) — Total revenue 1,197 — 1,175 — 94,507 (2,372 ) 94,507 Costs and Expenses: Programming and production — — — — 29,692 — 29,692 Other operating and administrative 947 — 1,175 1,023 27,321 (2,372 ) 28,094 Advertising, marketing and promotion — — — — 7,036 — 7,036 Depreciation 46 — — — 8,235 — 8,281 Amortization 5 — — — 2,731 — 2,736 Other operating gains — — — — (341 ) — (341 ) Total costs and expenses 998 — 1,175 1,023 74,674 (2,372 ) 75,498 Operating income (loss) 199 — — (1,023 ) 19,833 — 19,009 Interest expense (2,644 ) (12 ) (190 ) (430 ) (266 ) — (3,542 ) Investment and other income (loss), net 13,638 13,604 12,021 6,694 5,054 (51,236 ) (225 ) Income (loss) before income taxes 11,193 13,592 11,831 5,241 24,621 (51,236 ) 15,242 Income tax (expense) benefit 538 8 40 (4 ) (3,962 ) — (3,380 ) Net income (loss) 11,731 13,600 11,871 5,237 20,659 (51,236 ) 11,862 Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 131 — 131 Net income (loss) attributable to Comcast Corporation $ 11,731 $ 13,600 $ 11,871 $ 5,237 $ 20,528 $ (51,236 ) $ 11,731 Comprehensive income (loss) attributable to Comcast Corporation $ 10,908 $ 13,623 $ 11,873 $ 5,279 $ 19,553 $ (50,328 ) $ 10,908 Condensed Consolidating Statement of Income For the Year Ended December 31, 2017 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 85,029 $ — $ 85,029 Management fee revenue 1,128 — 1,109 — — (2,237 ) — Total revenue 1,128 — 1,109 — 85,029 (2,237 ) 85,029 Costs and Expenses: Programming and production — — — — 25,355 — 25,355 Other operating and administrative 766 — 1,109 1,044 24,767 (2,237 ) 25,449 Advertising, marketing and promotion — — — — 6,519 — 6,519 Depreciation 31 — — — 7,883 — 7,914 Amortization 6 — — — 2,210 — 2,216 Other operating gains — — — — (442 ) — (442 ) Total costs and expenses 803 — 1,109 1,044 66,292 (2,237 ) 67,011 Operating income (loss) 325 — — (1,044 ) 18,737 — 18,018 Interest expense (2,172 ) (12 ) (207 ) (456 ) (239 ) — (3,086 ) Investment and other income (loss), net 24,076 21,767 19,610 6,584 5,545 (77,161 ) 421 Income (loss) before income taxes 22,229 21,755 19,403 5,084 24,043 (77,161 ) 15,353 Income tax (expense) benefit 506 156 71 (4 ) 6,840 — 7,569 Net income (loss) 22,735 21,911 19,474 5,080 30,883 (77,161 ) 22,922 Less: Net income loss attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 187 — 187 Net income (loss) attributable to Comcast Corporation $ 22,735 $ 21,911 $ 19,474 $ 5,080 $ 30,696 $ (77,161 ) $ 22,735 Comprehensive income (loss) attributable to Comcast Corporation $ 22,822 $ 21,909 $ 19,477 $ 5,054 $ 30,558 $ (76,998 ) $ 22,822 Condensed Consolidating Statement of Income For the Year Ended December 31, 2016 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 80,736 $ — $ 80,736 Management fee revenue 1,067 — 1,049 — — (2,116 ) — Total revenue 1,067 — 1,049 — 80,736 (2,116 ) 80,736 Costs and Expenses: Programming and production — — — — 24,348 — 24,348 Other operating and administrative 813 — 1,049 932 23,162 (2,116 ) 23,840 Advertising, marketing and promotion — — — — 6,291 — 6,291 Depreciation 28 — — — 7,436 — 7,464 Amortization 6 — — — 1,956 — 1,962 Other operating gains — — — — — — — Total costs and expenses 847 — 1,049 932 63,193 (2,116 ) 63,905 Operating income (loss) 220 — — (932 ) 17,543 — 16,831 Interest expense (1,941 ) (12 ) (239 ) (456 ) (294 ) — (2,942 ) Investment and other income (loss), net 9,799 9,289 8,703 5,572 4,515 (37,441 ) 437 Income (loss) before income taxes 8,078 9,277 8,464 4,184 21,764 (37,441 ) 14,326 Income tax (expense) benefit 600 6 84 (13 ) (5,975 ) — (5,298 ) Net income (loss) 8,678 9,283 8,548 4,171 15,789 (37,441 ) 9,028 Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 350 — 350 Net income (loss) attributable to Comcast Corporation $ 8,678 $ 9,283 $ 8,548 $ 4,171 $ 15,439 $ (37,441 ) $ 8,678 Comprehensive income (loss) attributable to Comcast Corporation $ 8,950 $ 9,325 $ 8,554 $ 4,248 $ 15,529 $ (37,656 ) $ 8,950 Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2018 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ (2,245 ) $ 126 $ (112 ) $ (1,430 ) $ 27,958 $ — $ 24,297 Investing Activities: Net transactions with affiliates (26,179 ) (575 ) 112 1,336 25,306 — — Capital expenditures (27 ) — — — (9,747 ) — (9,774 ) Cash paid for intangible assets (4 ) — — — (1,931 ) — (1,935 ) Acquisitions and construction of real estate properties (105 ) — — — (38 ) — (143 ) Construction of Universal Beijing Resort — — — — (460 ) — (460 ) Acquisitions, net of cash acquired — — — — (38,219 ) — (38,219 ) Proceeds from sales of businesses and investments — — — 68 73 — 141 Purchases of investments (126 ) — — (50 ) (1,081 ) — (1,257 ) Deposits — — — — — — — Other 148 449 — — 196 — 793 Net cash provided by (used in) investing activities (26,293 ) (126 ) 112 1,354 (25,901 ) — (50,854 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net (902 ) — — — 1,281 — 379 Proceeds from borrowings 44,113 — — — 668 — 44,781 Repurchases and repayments of debt (5,737 ) — — (4 ) (3,057 ) — (8,798 ) Repurchases of common stock under repurchase program and employee plans (5,320 ) — — — — — (5,320 ) Dividends paid (3,352 ) — — — — — (3,352 ) Purchase of Universal Studios Japan noncontrolling interests — — — — — — — Issuances of common stock — — — — — — — Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (277 ) — (277 ) Other (201 ) — — — (72 ) — (273 ) Net cash provided by (used in) financing activities 28,601 — — (4 ) (1,457 ) — 27,140 Impact of foreign currency on cash, cash equivalents and restricted cash (63 ) — — — (182 ) — (245 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — (80 ) 418 — 338 Cash, cash equivalents and restricted cash, beginning of year — — — 496 3,075 — 3,571 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 416 $ 3,493 $ — $ 3,909 Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2017 (in millions) Comcast Parent Comcast Holdings CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ 151 $ 15 $ (147 ) $ (1,439 ) $ 22,681 $ — $ 21,261 Investing Activities: Net transactions with affiliates 5,578 (5 ) 757 1,447 (7,777 ) — — Capital expenditures (12 ) — — — (9,538 ) — (9,550 ) Cash paid for intangible assets (4 ) — — — (1,601 ) — (1,605 ) Acquisitions and construction of real estate properties (267 ) — — — (151 ) — (418 ) Construction of Universal Beijing Resort — — — — (71 ) — (71 ) Acquisitions, net of cash acquired — — — — (532 ) — (532 ) Proceeds from sales of businesses and investments — — — 14 136 — 150 Purchases of investments (70 ) (10 ) (60 ) (62 ) (2,090 ) — (2,292 ) Deposits — — — — — — — Other 101 — — 58 626 — 785 Net cash provided by (used in) investing activities 5,326 (15 ) 697 1,457 (20,998 ) — (13,533 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net (837 ) — — — (1,068 ) — (1,905 ) Proceeds from borrowings 5,997 — — — 5,469 — 11,466 Repurchases and repayments of debt (2,288 ) — (550 ) (4 ) (3,522 ) — (6,364 ) Repurchases of common stock under repurchase program and employee plans (5,435 ) — — — — — (5,435 ) Dividends paid (2,883 ) — — — — — (2,883 ) Purchase of Universal Studios Japan noncontrolling interests — — — — (2,299 ) — (2,299 ) Issuances of common stock — — — — — — — Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (252 ) — (252 ) Other (31 ) — — — 131 — 100 Net cash provided by (used in) financing activities (5,477 ) — (550 ) (4 ) (1,541 ) — (7,572 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — 14 142 — 156 Cash, cash equivalents and restricted cash, beginning of year — — — 482 2,933 — 3,415 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 496 $ 3,075 $ — $ 3,571 Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2016 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ 349 $ (336 ) $ (100 ) $ (1,453 ) $ 21,231 $ — $ 19,691 Investing Activities: Net transactions with affiliates (1,956 ) 336 100 2,642 (1,122 ) — — Capital expenditures (13 ) — — — (9,122 ) — (9,135 ) Cash paid for intangible assets (9 ) — — — (1,543 ) — (1,552 ) Acquisitions and construction of real estate properties (35 ) — — — (393 ) — (428 ) Construction of Universal Beijing Resort — — — — (22 ) — (22 ) Acquisitions, net of cash acquired — — — — (3,929 ) — (3,929 ) Proceeds from sales of businesses and investments — — — 104 114 — 218 Purchases of investments (40 ) — — (210 ) (1,447 ) — (1,697 ) Deposits — — — — (1,749 ) — (1,749 ) Other (108 ) — — (35 ) 172 — 29 Net cash provided by (used in) investing activities (2,161 ) 336 100 2,501 (19,041 ) — (18,265 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net 1,339 — — — 451 — 1,790 Proceeds from borrowings 9,231 — — — — — 9,231 Repurchases and repayments of debt (750 ) — — (1,005 ) (1,297 ) — (3,052 ) Repurchases of common stock under repurchase program and employee plans (5,352 ) — — — — — (5,352 ) Dividends paid (2,601 ) — — — — — (2,601 ) Issuances of common stock 23 — — — — — 23 Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (253 ) — (253 ) Other (78 ) — — 25 (167 ) — (220 ) Net cash provided by (used in) financing activities 1,812 — — (980 ) (1,266 ) — (434 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — 68 924 — 992 Cash, cash equivalents and restricted cash, beginning of year — — — 414 2,009 — 2,423 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 482 $ 2,933 $ — $ 3,415 Condensed Consolidating Balance Sheet December 31, 2018 (in millions) Comcast Parent Comcast Holdings CCCL Parent NBCUniversal Media Parent Non- Guarantor Subsidiaries Elimination and Consolidation Adjustments Consolidated Comcast Corporation Assets Cash and cash equivalents $ — $ — $ — $ 416 $ 3,398 $ — $ 3,814 Receivables, net — — — — 11,104 — 11,104 Programming rights — — — — 3,746 — 3,746 Other current assets 66 20 — 28 3,070 — 3,184 Total current assets 66 20 — 444 21,318 — 21,848 Film and television costs — — — — 7,837 — 7,837 Investments 270 11 143 790 6,669 — 7,883 Investments in and amounts due from subsidiaries eliminated upon consolidation 157,264 147,028 130,214 53,853 97,872 (586,231 ) — Property and equipment, net 670 — — — 43,767 — 44,437 Franchise rights — — — — 59,365 — 59,365 Goodwill — — — — 66,154 — 66,154 Other intangible assets, net 11 — — — 38,347 — 38,358 Other noncurrent assets, net 1,057 208 — 85 4,910 (458 ) 5,802 Total assets $ 159,338 $ 147,267 $ 130,357 $ 55,172 $ 346,239 $ (586,689 ) $ 251,684 Liabilities and Equity Accounts payable and accrued expenses related to trade creditors $ 2 $ — $ — $ — $ 8,492 $ — $ 8,494 Accrued participations and residuals — — — — 1,808 — 1,808 Deferred revenue — — — — 2,182 — 2,182 Accrued expenses and other current liabilities 2,357 150 360 282 7,572 — 10,721 Current portion of long-term debt 699 — — 4 3,695 — 4,398 Total current liabilities 3,058 150 360 286 23,749 — 27,603 Long-term debt, less current portion 81,661 146 2,100 7,748 15,690 — 107,345 Deferred income taxes — 314 — 65 27,734 (524 ) 27,589 Other noncurrent liabilities 3,006 — — 1,201 11,056 66 15,329 Redeemable noncontrolling interests and redeemable subsidiary preferred stock — — — — 1,316 — 1,316 Equity: Common stock 54 — — — — — 54 Other shareholders’ equity 71,559 146,657 127,897 45,872 265,805 (586,231 ) 71,559 Total Comcast Corporation shareholders’ equity 71,613 146,657 127,897 45,872 265,805 (586,231 ) 71,613 Noncontrolling interests — — — — 889 — 889 Total equity 71,613 146,657 127,897 45,872 266,694 (586,231 ) 72,502 Total liabilities and equity $ 159,338 $ 147,267 $ 130,357 $ 55,172 $ 346,239 $ (586,689 ) $ 251,684 Condensed Consolidating Balance Sheet December 31, 2017 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Assets Cash and cash equivalents $ — $ — $ — $ 496 $ 2,932 $ — $ 3,428 Receivables, net — — — — 8,834 — 8,834 Programming rights — — — — 1,613 — 1,613 Other current assets 60 — 7 25 2,376 — 2,468 Total current assets 60 — 7 521 15,755 — 16,343 Film and television costs — — — — 7,087 — 7,087 Investments 146 21 108 693 5,963 — 6,931 Investments in and amounts due from subsidiaries eliminated upon consolidation 117,164 142,519 139,528 50,102 113,332 (562,645 ) — Property and equipment, net 551 — — — 37,919 — 38,470 Franchise rights — — — — 59,364 — 59,364 Goodwill — — — — 36,780 — 36,780 Other intangible assets, net 12 — — — 18,121 — 18,133 Other noncurrent assets, net 435 708 — 88 3,437 (314 ) 4,354 Total assets $ 118,368 $ 143,248 $ 139,643 $ 51,404 $ 297,758 $ (562,959 ) $ 187,462 Liabilities and Equity Accounts payable and accrued expenses related to trade creditors $ 16 $ — $ — $ — $ 6,892 $ — $ 6,908 Accrued participations and residuals — — — — 1,644 — 1,644 Deferred revenue — — — — 1,687 — 1,687 Accrued expenses and other current liabilities 1,888 92 333 326 3,981 — 6,620 Current portion of long-term debt 2,810 — — 4 2,320 — 5,134 Total current liabilities 4,714 92 333 330 16,524 — 21,993 Long-term debt, less current portion 42,428 140 2,100 7,751 7,003 — 59,422 Deferred income taxes — 285 — 67 24,250 (343 ) 24,259 Other noncurrent liabilities 2,610 — — 1,128 7,205 29 10,972 Redeemable noncontrolling interests and redeemable subsidiary preferred stock — — — — 1,357 — 1,357 Equity: Common stock 55 — — — — — 55 Other shareholders’ equity 68,561 142,731 137,210 42,128 240,576 (562,645 ) 68,561 Total Comcast Corporation shareholders’ equity 68,616 142,731 137,210 42,128 240,576 (562,645 ) 68,616 Noncontrolling interests — — — — 843 — 843 Total equity 68,616 142,731 137,210 42,128 241,419 (562,645 ) 69,459 Total liabilities and equity $ 118,368 $ 143,248 $ 139,643 $ 51,404 $ 297,758 $ (562,959 ) $ 187,462

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Related Party Transactions	Note 15: Related Party Transactions In the ordinary course of our business, we enter into transactions with Comcast. We generate revenue from Comcast primarily from the distribution of our cable network programming, the fees received under retransmission consent agreements in our Broadcast Television segment and, to a lesser extent, the sale of advertising and our owned programming, and we incur expenses primarily related to advertising and various support services provided by Comcast to us. In September 2016, as part of the Comcast cash management process, we and Comcast amended and restated our revolving credit agreements to increase the amount that we can borrow from Comcast and that Comcast can borrow from us from $3 billion to $5 billion and to extend the maturity date to 2026. Depending on the receivable or payable position, amounts owed by us to Comcast or to us by Comcast under the revolving credit agreements are presented under the captions “note payable to Comcast” and “note receivable from Comcast,” respectively, in our consolidated balance sheet and are presented as current since the amounts include daily borrowings and repayments throughout the year based on our working capital needs. The revolving credit agreements bear interest at floating rates equal to the interest rate calculation under Comcast’s revolving credit facility. The interest rate on Comcast’s revolving credit facility consists of a base rate plus a borrowing margin that is determined based on Comcast’s credit rating. As of December 31, 2018 , the borrowing margin for London Interbank Offered Rate-based borrowings was 1.00% . Comcast is also the counterparty to one of our contractual obligations. As of both December 31, 2018 and 2017 , the carrying value of the liability associated with this contractual obligation was $383 million . Senior Notes Exchange In October 2017, we and Comcast completed a debt exchange transaction. Comcast issued $2.0 billion aggregate principal amount of new 3.97% senior notes due 2047, $2.0 billion aggregate principal amount of new 4.00% senior notes due 2049, and $1.5 billion aggregate principal amount of new 4.05% senior notes due 2052 in exchange for $3.9 billion aggregate principal amount of certain series of outstanding senior notes issued by Comcast and us, including $442 million of our 6.40% senior notes due 2040. The new notes are fully and unconditionally guaranteed by us and CCCL Parent. In connection with the exchange transaction, we issued $610 million of 4.00% notes due 2049 to Comcast. The debt exchange transaction was accounted for as a debt extinguishment, and therefore we recorded a charge of $157 million to interest expense upon retirement of the old notes. The following tables present transactions with Comcast and its consolidated subsidiaries that are included in our consolidated financial statements. Consolidated Statement of Income Year ended December 31 (in millions) 2018 2017 2016 Transactions with Comcast and Consolidated Subsidiaries Revenue $ 2,156 $ 1,837 $ 1,742 Total costs and expenses $ (245 ) $ (214 ) $ (220 ) Interest expense and investment and other income (loss), net $ (54 ) $ (250 ) $ (69 ) Consolidated Balance Sheet December 31 (in millions) 2018 2017 Transactions with Comcast and Consolidated Subsidiaries Receivables, net $ 464 $ 326 Note receivable from Comcast $ 2,054 — Accounts payable and accrued expenses related to trade creditors $ 78 $ 54 Accrued expenses and other current liabilities $ 32 $ 50 Note payable to Comcast $ 54 $ 1,831 Long-term debt $ 701 $ 610 Other noncurrent liabilities $ 410 $ 389 Distributions to NBCUniversal Holdings In addition to the transaction amounts presented in the table above, we make distributions to NBCUniversal Holdings on a periodic basis to enable its owners to meet their obligations to pay taxes on taxable income generated by our businesses. We also make quarterly distributions to NBCUniversal Holdings to enable it to make its required quarterly payments to NBCUniversal Enterprise at an initial annual rate of 8.25% on the $9.4 billion aggregate liquidation preference of its preferred units. On March 1, 2023, and thereafter on every fifth anniversary of such date, this rate will reset to 7.44% plus the yield on actively traded United States Treasury securities having a 5 year maturity. These distributions are presented under the caption “distributions to member” in our consolidated statement of cash flows. Share-Based Compensation Comcast maintains share-based compensation plans that consist primarily of awards of restricted share units (“RSUs”) and stock options to certain employees and directors as part of its approach to long-term incentive compensation. Additionally, through its employee stock purchase plans, employees are able to purchase shares of Comcast common stock at a discount through payroll deductions. The cost associated with Comcast’s share-based compensation is based on an award’s estimated fair value at the date of grant and is recognized over the period in which any related services are provided. RSUs are valued based on the closing price of Comcast common stock on the date of grant and are discounted for the lack of dividends, if any, during the vesting period. Stock options are valued using the Black-Scholes option pricing model. Certain of our employees participate in these plans and the expense associated with their participation is settled in cash with Comcast. In 2018, 2017 and 2016, we recognized share-based compensation expense of $151 million, $133 million and $99 million, respectively. As of December 31, 2018, we had unrecognized pretax compensation expense of $270 million related to nonvested Comcast RSUs and unrecognized pretax compensation expense of $23 million related to nonvested Comcast stock options that will be recognized over a weighted-average period of approximately 1.6 years and 1.0 years, respectively.

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule II - Valuation and Qualifying Accounts	Comcast Corporation and Subsidiaries Schedule II – Valuation and Qualifying Accounts Year ended December 31, 2018 , 2017 and 2016 Year ended December 31 (in millions) Balance at Beginning Additions Charged to Deductions from Balance at End 2018 Allowance for doubtful accounts $ 288 $ 616 $ 552 $ 352 Valuation allowance on deferred tax assets 377 367 112 632 2017 Allowance for doubtful accounts $ 250 $ 554 $ 516 $ 288 Valuation allowance on deferred tax assets 266 111 — 377 2016 Allowance for doubtful accounts $ 226 $ 558 $ 534 $ 250 Valuation allowance on deferred tax assets 342 23 99 266
NBCUniversal Media LLC [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule II - Valuation and Qualifying Accounts	NBCUniversal Media, LLC Schedule II – Valuation and Qualifying Accounts Year ended December 31, 2018 , 2017 and 2016 Year ended December 31 (in millions) Balance at Beginning Additions Charged to Deductions from Balance at End 2018 Allowance for doubtful accounts $ 88 $ 32 $ 21 $ 99 Valuation allowance on deferred tax assets 87 13 27 73 2017 Allowance for doubtful accounts $ 84 $ 23 $ 19 $ 88 Valuation allowance on deferred tax assets 72 15 — 87 2016 Allowance for doubtful accounts $ 69 $ 26 $ 11 $ 84 Valuation allowance on deferred tax assets 71 23 22 72

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	12 Months Ended
	Dec. 31, 2018
Recent Accounting Pronouncements [Line Items]
Basis of Presentation	The accompanying consolidated financial statements include all entities in which we have a controlling voting interest and variable interest entities (“VIEs”) required to be consolidated in accordance with generally accepted accounting principles in the United States (“GAAP”).
Foreign Currency Translation	We translate assets and liabilities of our foreign operations where the functional currency is the local currency, primarily the British pound, euro, Japanese yen and Chinese renminbi, into U.S. dollars at the exchange rate as of the balance sheet date and translate revenue and expenses using average monthly exchange rates. The related translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in our consolidated balance sheet. Any foreign currency transaction gains or losses are included in our consolidated statement of income.
Use of Estimates	Our consolidated financial statements are prepared in accordance with GAAP, which require us to select accounting policies, including in certain cases industry-specific policies, and make estimates that affect the reported amount of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and contingent liabilities. Actual results could differ from these estimates. We believe that the judgments and related estimates for the following items are critical in the preparation of our consolidated financial statements: • valuation and impairment testing of cable franchise rights (see Note 12) • film and television costs (see Note 4) • fair value of acquisition-related assets and liabilities (see Note 8) In addition, the following accounting policies are specific to the industries in which we operate: • capitalization and amortization of film and television costs (see Note 4) • costs for connecting customers to our cable systems (see Note 11) Information on other accounting policies and methods that we use in the preparation of our consolidated financial statements are included, where applicable, in their respective footnotes that follow. Below is a discussion of accounting policies and methods used in our consolidated financial statements that are not presented within other footnotes.
Advertising Cost	Advertising costs are expensed as incurred.
Cash Equivalents	The carrying amounts of our cash equivalents approximate their fair values. Our cash equivalents consist primarily of money market funds and U.S. government obligations, as well as commercial paper and certificates of deposit with maturities of three months or less when purchased.
Derivative Financial Instruments	We use derivative financial instruments to manage our exposure to the risks associated with fluctuations in interest rates, foreign exchange rates and equity prices. Our objective is to manage the financial and operational exposure arising from these risks by offsetting gains and losses on the underlying exposures with gains and losses on the derivatives used to economically hedge them. Our derivative financial instruments are recorded in our consolidated balance sheet at fair value. Refer to Note 7 for further information on foreign exchange derivatives related to debt. The impact of our remaining derivative financial instruments on our consolidated financial statements was not material in any of the periods presented.
Fair Value Measurements	The accounting guidance related to fair value measurements establishes a hierarchy based on the types of inputs used for the various valuation techniques (market approach, income approach and cost approach). The levels of the hierarchy are described below. • Level 1: Values are determined using quoted market prices for identical financial instruments in an active market • Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable • Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation We use these levels of hierarchy to measure the fair value of certain financial instruments on a recurring basis, such as for investments; on a non-recurring basis, such as for acquisitions and impairment testing; for disclosure purposes, such as for long-term debt; and for other applications, as discussed in their respective footnotes. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation and classification within the fair value hierarchy.
Asset Retirement Obligations	Certain of our cable franchise agreements and lease agreements contain provisions requiring us to restore facilities or remove property in the event that the franchise or lease agreement is not renewed. We expect to continually renew our cable franchise agreements and therefore cannot reasonably estimate liabilities associated with such agreements. A remote possibility exists that franchise agreements could be terminated unexpectedly, which could result in us incurring significant expense in complying with restoration or removal provisions. We do not have any material liabilities related to asset retirements recorded in our consolidated financial statements.
Revenue Recognition	Cable Communications Segment Residential Our Cable Communications segment generates revenue from residential customers that subscribe to our high-speed internet, video, voice, and security and automation services, which we market individually and as bundled services at a discounted rate in the United States. Revenue from residential customers that purchase bundled services at a discounted rate is allocated between the separate services based on the respective stand-alone selling prices. The stand-alone selling prices are determined based on the current prices at which we separately sell the cable services. Significant judgment is used to determine performance obligations that should be accounted for separately and the allocation of revenue when services are combined in a bundle. Revenue related to our security and automation services is reported in other revenue. We recognize revenue from residential cable services as the services are provided on a monthly basis. Subscription rates and related charges vary according to the services and features customers receive. Customers are typically billed in advance and pay on a monthly basis. Installation fees are deferred and recognized as revenue over the period of benefit to the customer, which is less than a year for residential customers. While a portion of our residential customers are subject to contracts for their cable services, which are typically 2 years in length, based on our evaluation of the terms of these contracts, we recognize revenue for these cable services on a basis that is consistent with our customers that are not subject to contracts. Our cable services generally involve customer premise equipment, such as set-top boxes, cable modems and wireless gateways. The timing and pattern of recognition for customer premise equipment revenue are consistent with those of our residential cable services. Sales commissions related to our residential customers are expensed as incurred, as the related period of benefit is less than a year. Under the terms of our cable franchise agreements, we are generally required to pay the cable franchising authority an amount based on our gross video revenue. We generally pass these and other similar fees through to our cable services customers and classify these fees in the respective cable service revenue, with the corresponding costs included in other operating and administrative expenses. Business Services Our Cable Communications segment generates revenue from business customers that subscribe to a variety of products and services. Our small business services offerings primarily include high-speed internet services, as well as voice and video services, similar to those that we provide to our residential customers, and also include cloud-based solutions that provide file sharing, online backup and web conferencing, among other features. We also offer Ethernet network services that connect multiple locations and provide higher downstream and upstream speed options to medium-sized customers and larger enterprises, as well as advanced voice services. In addition, we provide cellular backhaul services to mobile network operators to help these customers manage their network bandwidth. Recently, we have expanded our enterprise service offerings to include a software-defined networking product and our managed solutions business to offer enterprise customers support related to Wi-Fi networks, router management, network security, business continuity risks and other services. We primarily offer our enterprise service offerings to Fortune 1000 companies and other large enterprises with multiple locations both within and outside of our cable distribution footprint where we have agreements with other companies to use their networks to provide coverage. We recognize revenue from business services as the services are provided on a monthly basis. Substantially all of our business customers are initially under contracts, with terms typically ranging from 2 years for small and medium-sized businesses to up to 5 years for larger enterprises. At any given time, the amount of future revenue to be earned related to fixed pricing under existing agreements is equal to approximately half of our annual business services revenue, of which the substantial majority will be recognized within 2 years . Customers with contracts may only discontinue service in accordance with the terms of their contracts. We receive payments from business customers based on a billing schedule established in our contracts, which is typically on a monthly basis. Installation revenue related to our business services customers and sales commissions are generally deferred and recognized over the respective contract terms. Advertising Our Cable Communications segment generates revenue from the sale of advertising and technology, tools and solutions relating to advertising businesses. As part of our distribution agreements with cable networks, we generally receive an allocation of scheduled advertising time that we sell to local, regional and national advertisers. In most cases, the available advertising units are sold by our sales force. We also represent the advertising sales efforts of other multichannel video providers in some markets. Since we are acting as the principal in these arrangements, we record the advertising that is sold in advertising revenue and the fees paid to multichannel video providers in other operating and administrative expenses. In some cases, we work with representation firms as an extension of our sales force to sell a portion of the advertising units allocated to us and record the revenue net of agency commissions. In addition, we generate revenue from the sale of advertising on digital platforms. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms and conditions are agreed upon. Advertising revenue from these arrangements is recognized in the period in which advertisements are aired or viewed. Payment terms vary by contract, although terms generally require payment within 30 to 60 days from when advertisements are aired or viewed. In addition, our advertising business also provides technology, tools, data-driven services and marketplace solutions to customers in the media industry, which allows advertisers to more effectively engage with their target audiences. Revenue earned in this manner is recognized when services are provided. NBCUniversal Segments Distribution Our Cable Networks segment generates distribution revenue from the distribution of our cable network programming to traditional and virtual multichannel video providers. Our Broadcast Television segment generates distribution revenue from the fees received under retransmission consent agreements and associated fees received from NBC-affiliated local broadcast television stations. Distribution revenue is accounted for as a license of functional intellectual property and is recognized as programming is provided on a monthly basis, generally under multiyear agreements. Monthly fees received under distribution agreements with multichannel video providers are generally based on the number of subscribers. Payment terms and conditions vary by contract type, although terms generally include payment within 30 to 60 days. Advertising Our Cable Networks and Broadcast Television segments generate advertising revenue from the sale of advertising on our cable and broadcast networks, our owned local broadcast television stations and various digital properties. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms are agreed upon. Advertising revenue is recognized, net of agency commissions, in the period in which advertisements are aired or viewed and payment occurs thereafter, with payment generally required within 30 days. In some instances, we guarantee audience ratings for the advertisements. To the extent there is a shortfall in contracts where the ratings were guaranteed, a portion of the revenue is deferred until the shortfall is settled, typically by providing additional advertising units generally within one year of the original airing. Theatrical Our Filmed Entertainment segment generates theatrical revenue from the worldwide theatrical release of our produced and acquired films for exhibition in movie theaters. Theatrical revenue is affected by the timing, nature and number of films released in movie theaters and their acceptance by audiences. It is also affected by the number of exhibition screens, ticket prices, the percentage of ticket sale retention by the exhibitors and the popularity of competing films at the time our films are released. We recognize theatrical revenue as the films are viewed and exhibited in theaters and payment generally occurs within 30 days after exhibition. Content Licensing Our Cable Networks, Broadcast Television and Filmed Entertainment segments generate revenue from the licensing of our owned film and television content in the United States and internationally to cable, broadcast and premium networks and subscription video on demand services. Our content licensing agreements generally include fixed pricing and span multiple years. For example, following a film’s theatrical release, our Filmed Entertainment segment may license the exhibition rights of a film to different customers over multiple successive distribution windows. We recognize revenue when the content is delivered and available for use by the licensee. When the term of an existing agreement is renewed or extended, we recognize revenue at the later of when the content is available or when the renewal or extension period begins. Payment terms and conditions vary by contract type, although payments are generally collected over the license term. The amount of future revenue to be earned related to fixed pricing under existing agreements primarily relates to our Filmed Entertainment segment, which at any given time equals approximately 1 to 2 years of our annual Filmed Entertainment content licensing revenue. The majority of this revenue will be recognized within 2 years. This amount may fluctuate from period to period depending on the timing of the releases and the availability of content under existing agreements and may not represent the total content licensing revenue expected to be recognized as it does not include revenue from future agreements or from variable pricing or optional purchases under existing agreements. For our content licensing agreements that include variable pricing, such as pricing based on the number of subscribers to a subscription video on demand service sold by our customers, we generally recognize revenue as our customers sell to their subscribers. Home Entertainment Our Filmed Entertainment segment generates revenue from the sale of our produced and acquired films on standard-definition digital video discs and Blu-ray discs (together, “DVDs”) and through digital distribution services. Our Cable Networks and Broadcast Television networks also generate revenue from the sale of owned programming on DVDs and through digital distribution services, which is reported in other revenue. We generally recognize revenue from DVD sales, net of estimated returns and customer incentives, on the date that DVDs are delivered to and made available for sale by retailers. Payment terms generally include payment within 60 to 90 days from delivery to the retailer. Theme Parks Our Theme Parks segment generates revenue primarily from ticket sales and guest spending at our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. Guest spending includes in-park spending on food, beverages and merchandise. We recognize revenue from theme park ticket sales when the tickets are used, generally within a year from the date of purchase. For annual passes, we generally recognize revenue on a straight-line basis over the period the pass is available to be used. We recognize revenue from guest spending at the point of sale. Sky Segment Direct-to-Consumer The majority of Sky’s revenue is direct-to-consumer, which primarily includes subscription revenue relating to the sale of video services to residential and business customers. Sky also provides high-speed internet, voice and wireless phone services in select countries. Generally, all of our residential customers are initially under contracts, with terms typically ranging from rolling monthly to 2 years , depending on the product and territory, and may only discontinue service in accordance with the terms of their contracts. Subscription rates and related charges vary according to the services and features customers receive and the types of equipment they use. Sky’s video, high-speed internet, voice and wireless phone services generally may be sold individually or in bundles. We recognize revenue from video, high-speed internet, voice and wireless phone services as the services are provided on a monthly basis. At any given time, the amount of future revenue to be earned related to existing agreements is equal to less than half of our annual subscription revenue, which generally will be recognized within 2 years . Content Sky’s content revenue includes revenue from the distribution of its channels on third-party platforms and the licensing of owned programming to third-party video providers. Refer to the NBCUniversal segment discussion of distribution and content licensing revenue for accounting policies for these types of arrangements. Advertising Sky sells advertising and sponsorships across its owned channels and where it represents the sales efforts of third-party channels. Sky also sells targeted advertising in the U.K., Ireland and Italy, and generates revenue from online and mobile advertising and advertising across its On Demand services. Advertising revenue is recognized when the advertising is aired or viewed.
Film And Television Costs	We capitalize film and television production costs, including direct costs, production overhead, print costs, development costs and interest. We amortize capitalized film and television production costs, including acquired libraries, and accrue costs associated with participation and residual payments to programming and production expenses. We generally record the amortization and the accrued costs using the individual film forecast computation method, which amortizes the costs in the same ratio as the associated ultimate revenue. Estimates of ultimate revenue and total costs are based on anticipated release patterns, public acceptance and historical results for similar productions. Unamortized film and television production costs, including acquired libraries, are stated at the lower of unamortized cost or fair value. We do not capitalize costs related to the distribution of a film in movie theaters or the licensing or sale of a film or television production, which primarily include costs associated with marketing and distribution. In determining the method of amortization and estimated life of an acquired film or television library, we generally use the method and the life that most closely follow the undiscounted cash flows over the estimated life of the asset. When an event or a change in circumstance occurs that was known or knowable as of the balance sheet date and that indicates the fair value of a film is less than its unamortized costs, we determine the fair value of the film and record an impairment charge for the amount by which the unamortized capitalized costs exceed the film’s fair value. The estimated fair value of a production is based on Level 3 inputs that primarily use an analysis of future expected cash flows. Adjustments to capitalized film production costs were not material in any of the periods presented. We may enter into cofinancing arrangements with third parties to jointly finance or distribute certain of our film productions. Cofinancing arrangements can take various forms, but in most cases involve the grant of an economic interest in a film to an investor. The number of investors and the terms of these arrangements can vary, although investors generally assume the full risks and rewards for the portion of the film acquired in these arrangements. We account for the proceeds received from a third-party investor under these arrangements as a reduction to our capitalized film costs. Under these arrangements, the investor owns an undivided copyright interest in the film, and therefore in each period we record either a charge or a benefit to programming and production expenses to reflect the estimate of the third-party investor’s interest in the profit or loss of the film. The estimate of the third-party investor’s interest in the profit or loss of a film is determined using the ratio of actual revenue earned to date to the ultimate revenue expected to be recognized over the film’s useful life. We capitalize the costs of programming content that we license but do not own, including rights to multiyear, live-event sports programming, at the earlier of when payments are made for the programming or when the license period begins and the content is made available for use. We amortize capitalized programming costs as the associated programs are broadcast. We generally amortize multiyear, live-event sports programming rights using the ratio of the current period revenue to the estimated ultimate revenue or under the terms of the contract. Programming costs are recorded at the lower of unamortized cost or net realizable value on a program by program, package, channel or daypart basis. A daypart is an aggregation of programs broadcast during a particular time of day or programs of a similar type. Programming acquired by our Cable Networks segment is primarily tested on a channel basis for impairment, whereas programming acquired by our Broadcast Television segment is tested on a daypart basis. If we determine that the estimates of future cash flows are insufficient or if there is no plan to broadcast certain programming, we recognize an impairment charge to programming and production expenses.
Earnings Per Share	Diluted earnings per common share attributable to Comcast Corporation shareholders (“diluted EPS”) considers the impact of potentially dilutive securities using the treasury stock method. Our potentially dilutive securities include potential common shares related to our stock options and our restricted share units (“RSUs”). Diluted EPS excludes the impact of potential common shares related to our stock options in periods in which the combination of the option exercise price and the associated unrecognized compensation expense is greater than the average market price of our common stock
Recent Accounting Pronouncements	Revenue Recognition In May 2014, the Financial Accounting Standards Board (“FASB”) updated the accounting guidance related to revenue recognition. The updated accounting guidance provides a single, contract-based revenue recognition model to help improve financial reporting by providing clearer guidance on when an entity should recognize revenue and by reducing the number of standards to which an entity has to refer. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the updated guidance on January 1, 2018 on a full retrospective basis, which required us to reflect the impact of the updated guidance for all periods presented. Upon adoption, we also implemented changes in our presentation of certain revenues and expenses, primarily in our Cable Communications segment. The adoption of the new standard did not have a material impact on our consolidated results of operations or financial position for any period presented. The updated guidance also requires additional disclosures regarding the nature, timing and uncertainty of our revenue transactions. See Note 3 for additional information. The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 84,526 $ 503 $ 85,029 Total costs and expenses $ 66,539 $ 472 $ 67,011 Operating income $ 17,987 $ 31 $ 18,018 Net income attributable to Comcast Corporation $ 22,714 $ 21 $ 22,735 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 80,403 $ 333 $ 80,736 Total costs and expenses $ 63,544 $ 361 $ 63,905 Operating income $ 16,859 $ (28 ) $ 16,831 Net income attributable to Comcast Corporation $ 8,695 $ (17 ) $ 8,678 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 16,060 $ 283 $ 16,343 Film and television costs $ 7,076 $ 11 $ 7,087 Other intangible assets, net $ 18,779 $ (646 ) $ 18,133 Other noncurrent assets, net $ 3,489 $ 865 $ 4,354 Total assets $ 186,949 $ 513 $ 187,462 Total current liabilities $ 21,561 $ 432 $ 21,993 Deferred income taxes $ 24,256 $ 3 $ 24,259 Other noncurrent liabilities $ 10,904 $ 68 $ 10,972 Total equity $ 69,449 $ 10 $ 69,459 Total liabilities and equity $ 186,949 $ 513 $ 187,462 Cable Communications A summary of the changes implemented for the Cable Communications segment is presented below. Changes to Presentation of Revenue and Related Costs • Revenue from our residential video services decreased with corresponding increases to high-speed internet and voice revenue due to a change in the allocation of revenue among our cable services included in a bundle that our residential customers purchase at a discount. • Revenue from franchise and other regulatory fees, which was previously presented in other revenue, is now presented with the corresponding cable services. This resulted in increases to video, voice and business services revenue. • Residential customer late fees are now presented in other revenue. These fees were previously presented as a reduction to other operating costs and expenses. • Certain costs, including costs related to the fulfillment of contracts with customers, are now presented as other assets and the related costs are recognized over time in operating costs and expenses, which are comprised of total costs and expenses, excluding depreciation and amortization expense and other operating gains. These amounts were previously presented as intangible assets, and the expenses were previously presented in amortization expense. The payments related to these assets are now presented in net cash provided by operating activities rather than in cash paid for intangible assets in our consolidated statement of cash flows. Changes to the Timing of Recognition of Revenue and Related Costs • Revenue for upfront installation services that are not distinct and commission expenses are now recognized as revenue and operating costs and expenses, respectively, over a period of time rather than recognized immediately as they were previously. We recorded a deferred revenue liability related to upfront installation fees that are not distinct services, which required us to allocate the installation fees to the respective service. The installation fees are generally recognized as revenue over the period that the fee would influence a customer to renew their service. This period is less than a year for Cable Communications residential customers and the term of the related contract for business services customers. Incremental costs to obtain a contract with a customer, such as commissions for our business customers, are now deferred and recognized over the contract term. Sales commissions related to our Cable Communications residential customers are expensed as incurred as the related period of benefit is less than a year. The tables below present the effects these changes had on our Cable Communications segment revenue, operating costs and expenses, and depreciation and amortization expense as a result of the adoption of updated guidance for the prior year periods. Previously reported amounts are based on amounts previously presented in the segment information footnote. Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 14,769 $ 912 $ 15,681 Video 23,129 (255 ) 22,874 Voice 3,391 699 4,090 Business services 6,216 221 6,437 Advertising 2,257 193 2,450 Other 2,757 (1,219 ) 1,538 Total Cable Communications revenue $ 52,519 $ 551 $ 53,070 Operating costs and expenses $ 31,349 $ 653 $ 32,002 Depreciation and amortization expense $ 8,143 $ (137 ) $ 8,006 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 13,532 $ 889 $ 14,421 Video 22,357 (153 ) 22,204 Voice 3,540 619 4,159 Business services 5,514 191 5,705 Advertising 2,476 150 2,626 Other 2,629 (1,167 ) 1,462 Total Cable Communications revenue $ 50,048 $ 529 $ 50,577 Operating costs and expenses $ 29,939 $ 624 $ 30,563 Depreciation and amortization expense $ 7,670 $ (132 ) $ 7,538 NBCUniversal Segments The adoption of the updated guidance impacted the timing of recognition for some of our revenue contracts, primarily for content licensing agreements. As a result of the adoption of the updated guidance, when the term of an existing content licensing agreement is renewed or extended, revenue is not recognized until the date when the renewal or extension period begins. Under the prior guidance, revenue for the content licensing renewal period was recognized on the date that the renewal was agreed to contractually. This change resulted in delayed revenue recognition for content licensing renewals or extensions in our Cable Networks, Broadcast Television and Filmed Entertainment segments. This change also impacted the timing of the related amortization of our film and television costs and participations and residuals expenses. The adoption of the updated guidance did not have a material impact on the results of operations or financial position for the NBCUniversal segments. Financial Assets and Financial Liabilities In January 2016, the FASB updated the accounting guidance related to the recognition and measurement of financial assets and financial liabilities. The updated accounting guidance, among other things, requires that all nonconsolidated equity investments, except those accounted for under the equity method, be measured at fair value and the changes in fair value be recognized in net income. On January 1, 2018, we adopted the updated guidance prospectively along with a related clarifying update and as a result, we recorded an immaterial cumulative effect adjustment to retained earnings, accumulated other comprehensive income (loss) and investments. See Note 10 for additional information. Restricted Cash In November 2016, the FASB updated the accounting guidance related to restricted cash. The new standard requires that the statement of cash flows present the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents, and a reconciliation of that total to amounts presented on the balance sheet. We adopted the updated guidance on January 1, 2018 and as required applied the retrospective transition method. The adoption did not have a material impact for any period presented. Leases In February 2016, the FASB updated the accounting guidance related to leases. The updated accounting guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases with the exception of short-term leases. The asset and liability are initially measured based on the present value of committed lease payments. For a lessee, the recognition, measurement and presentation of expenses and cash flows arising from a lease do not significantly change from previous guidance. For a lessor, the accounting applied is also largely unchanged from previous guidance. We will adopt the updated accounting guidance in the first quarter of 2019 and prior periods will not be adjusted. We are currently in the process of determining the impact that the updated accounting will have on our consolidated financial statements. See Note 17 for a summary of our undiscounted minimum rental commitments under operating leases as of December 31, 2018.
Investments	Nonmarketable Equity Securities We classify investments without readily determinable fair values that are not accounted for under the equity method as nonmarketable equity securities. The accounting guidance requires nonmarketable equity securities to be recorded at cost and adjusted to fair value at each reporting period. However, the guidance allows for a measurement alternative, which is to record the investments at cost, less impairment, if any, and subsequently adjust for observable price changes of identical or similar investments of the same issuer. We apply this measurement alternative to a majority of our nonmarketable equity securities. When an observable event occurs, we estimate the fair values of our nonmarketable equity securities based on Level 2 inputs that are derived from observable price changes of similar securities adjusted for insignificant differences in rights and obligations. The changes in value are recorded in realized and unrealized gains (losses) on equity securities, net. Equity Method We use the equity method to account for investments in which we have the ability to exercise significant influence over the investee’s operating and financial policies or in which we hold a significant partnership or limited liability company interest. Equity method investments are recorded at cost and are adjusted to recognize (1) our proportionate share of the investee’s net income or loss after the date of investment, (2) amortization of the recorded investment that exceeds our share of the book value of the investee’s net assets, (3) additional contributions made and dividends received, and (4) impairments resulting from other-than-temporary declines in fair value. For some investments, we record our share of the investee’s net income or loss one quarter in arrears due to the timing of our receipt of such information. Gains or losses on the sale of equity method investments are recorded to other income (loss), net. If an equity method investee were to issue additional securities that would change our proportionate share of the entity, we would recognize the change, if any, as a gain or loss to other income (loss), net. Marketable Equity Securities We classify publicly traded investments with readily determinable fair values that are not accounted for under the equity method as marketable equity securities. Marketable equity securities are recorded at cost and adjusted to fair value at each reporting period. The changes in fair value between measurement dates are recorded in realized and unrealized gains (losses) on equity securities, net. The fair values of our marketable equity securities are based on Level 1 inputs that use quoted market prices.
Impairment Testing of Investments	We review our investment portfolio, other than our marketable equity securities, each reporting period to determine whether there are identified events or circumstances that would indicate there is a decline in the fair value. For our nonpublic investments, if there are no identified events or circumstances that would have a significant adverse effect on the fair value of the investment, then the fair value is not estimated. For our equity method investments and held to maturity investments, if an investment is deemed to have experienced an other-than-temporary decline below its cost basis, we reduce the carrying amount of the investment to its quoted or estimated fair value, as applicable, and establish a new cost basis for the investment. For our nonmarketable equity securities, we record the impairment to realized and unrealized gains (losses) on equity securities, net. For our equity method investments and our held to maturity investments, we record the impairment to other income (loss), net.
Property and Equipment	Property and equipment are stated at cost. We capitalize improvements that extend asset lives and expense repairs and maintenance costs as incurred. We record depreciation using the straight-line method over the asset’s estimated useful life. For assets that are sold or retired, we remove the applicable cost and accumulated depreciation and, unless the gain or loss on disposition is presented separately, we recognize it as a component of depreciation expense. In accordance with the accounting guidance related to cable television companies, our Cable Communications segment capitalizes the costs associated with the construction of and improvements to our cable transmission and distribution facilities, including scalable infrastructure and line extensions; costs associated with acquiring and deploying new customer premise equipment; and costs associated with installation of our services. Costs capitalized include all direct costs for labor and materials, as well as various indirect costs. Costs incurred in connection with subsequent disconnects and reconnects are expensed as they are incurred. We evaluate the recoverability of our property and equipment whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of depreciation expense.
Goodwill	Goodwill is calculated as the excess of the consideration transferred over the identifiable net assets acquired in a business combination and represents the future economic benefits expected to arise from anticipated synergies and intangible assets acquired that do not qualify for separate recognition, including assembled workforce, noncontractual relationships and other agreements. We assess the recoverability of our goodwill annually, or more frequently whenever events or substantive changes in circumstances indicate that the carrying amount of a reporting unit may exceed its fair value. We test goodwill for impairment at the reporting unit level. To determine our reporting units, we evaluate the components one level below the segment level and we aggregate the components if they have similar economic characteristics. As a result of this assessment, our reporting units are generally the same as our reportable segments. We evaluate the determination of our reporting units used to test for impairment periodically or whenever events or substantive changes in circumstances occur. The assessment of recoverability may first consider qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. The quantitative assessment considers whether the carrying amount of a reporting unit exceeds its fair value, in which case an impairment charge is recorded to the extent the reporting unit’s carrying value exceeds its fair value. Unless presented separately, the impairment charge is included as a component of amortization expense.
Indefinite-Lived Intangible Assets	Indefinite-lived intangible assets consist primarily of our cable franchise rights. Our cable franchise rights represent the values we attributed to agreements with state and local authorities that allow access to homes and businesses in cable service areas acquired in business combinations. We do not amortize our cable franchise rights because we have determined that they meet the definition of indefinite-lived intangible assets since there are no legal, regulatory, contractual, competitive, economic or other factors which limit the period over which these rights will contribute to our cash flows. We reassess this determination periodically or whenever events or substantive changes in circumstances occur. We assess the recoverability of our cable franchise rights and other indefinite-lived intangible assets annually, or more frequently whenever events or substantive changes in circumstances indicate that the assets might be impaired. Our three Cable Communications divisions represent the unit of account we use to test for impairment of our cable franchise rights. We evaluate the unit of account used to test for impairment of our cable franchise rights and other indefinite-lived intangible assets periodically or whenever events or substantive changes in circumstances occur to ensure impairment testing is performed at an appropriate level. The assessment of recoverability may first consider qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. When performing a quantitative assessment, we estimate the fair value of our cable franchise rights and other indefinite-lived intangible assets primarily based on a discounted cash flow analysis that involves significant judgment. When analyzing the fair values indicated under the discounted cash flow models, we also consider multiples of Adjusted EBITDA generated by the underlying assets, current market transactions and profitability information. If the fair value of our cable franchise rights or other indefinite-lived intangible assets were less than the carrying amount, we would recognize an impairment charge for the difference between the estimated fair value and the carrying value of the assets. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any material impairment charges in any of the periods presented.
Finite-Lived Intangible Assets	Finite-lived intangible assets are subject to amortization and consist primarily of customer relationships acquired in business combinations, software, and intellectual property rights. Our finite-lived intangible assets are amortized primarily on a straight-line basis over their estimated useful life or the term of the associated agreement. We capitalize direct development costs associated with internal-use software, including external direct costs of material and services and payroll costs for employees devoting time to these software projects. We also capitalize costs associated with the purchase of software licenses. We generally amortize them on a straight-line basis over a period not to exceed five years . We expense maintenance and training costs, as well as costs incurred during the preliminary stage of a project, as they are incurred. We capitalize initial operating system software costs and amortize them over the life of the associated hardware. We evaluate the recoverability of our finite-lived intangible assets whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of amortization expense.
Share-Based Compensation	The cost associated with our share-based compensation is based on an award’s estimated fair value at the date of grant and is recognized over the period in which any related services are provided. RSUs are valued based on the closing price of our common stock on the date of grant and are discounted for the lack of dividends, if any, during the vesting period. We use the Black-Scholes option pricing model to estimate the fair value of stock option awards. The table below presents the weighted-average fair value on the date of grant of RSUs and stock options awarded under our various plans and the related weighted-average valuation assumptions.
Income Taxes	We base our provision for income taxes on our current period income, changes in our deferred income tax assets and liabilities, income tax rates, changes in estimates of our uncertain tax positions, tax planning opportunities available in the jurisdictions in which we operate and following the adoption of new accounting guidance related to share-based compensation in 2017, excess tax benefits or deficiencies that arise when the tax consequences of share-based compensation differ from amounts previously recognized in the statement of income. We recognize deferred tax assets and liabilities when there are temporary differences between the financial reporting basis and tax basis of our assets and liabilities and for the expected benefits of using net operating loss carryforwards. When a change in the tax rate or tax law has an impact on deferred taxes, we apply the change based on the years in which the temporary differences are expected to reverse. We record the change in our consolidated financial statements in the period of enactment. The determination of the income tax consequences of a business combination includes identifying the tax basis of assets and liabilities acquired and any contingencies associated with uncertain tax positions assumed or resulting from the business combination. Deferred tax assets and liabilities related to temporary differences of an acquired entity are recorded as of the date of the business combination and are based on our estimate of the ultimate tax basis that will be accepted by the various tax authorities. We record liabilities for contingencies associated with prior tax returns filed by the acquired entity based on criteria set forth in the appropriate accounting guidance. We adjust the deferred tax accounts and the liabilities periodically to reflect any revised estimated tax basis and any estimated settlements with the various tax authorities. The effects of these adjustments are recorded to income tax expense (benefit). From time to time, we engage in transactions in which the tax consequences may be subject to uncertainty. In these cases, we evaluate our tax position using the recognition threshold and the measurement attribute in accordance with the accounting guidance related to uncertain tax positions. Examples of these transactions include business acquisitions and dispositions, including consideration paid or received in connection with these transactions, certain financing transactions, and the allocation of income among state and local tax jurisdictions. Significant judgment is required in assessing and estimating the tax consequences of these transactions. We determine whether it is more likely than not that a tax position will be sustained on examination, including the resolution of any related appeals or litigation processes, based on the technical merits of the position. A tax position that meets the more-likely-than-not recognition threshold is measured to determine the amount of benefit to be recognized in our consolidated financial statements. We classify interest and penalties, if any, associated with our uncertain tax positions as a component of income tax expense (benefit).
NBCUniversal Media LLC [Member]
Recent Accounting Pronouncements [Line Items]
Basis of Presentation	The accompanying consolidated financial statements include all entities in which we have a controlling voting interest and variable interest entities (“VIEs”) required to be consolidated in accordance with generally accepted accounting principles in the United States (“GAAP”). Transactions between NBCUniversal and both Comcast and Comcast’s consolidated subsidiaries are reflected in these consolidated financial statements and disclosed as related party transactions when material.
Foreign Currency Translation	We translate assets and liabilities of our foreign operations where the functional currency is the local currency, primarily the Japanese yen, euro, British pound and Chinese renminbi, into U.S. dollars at the exchange rate as of the balance sheet date and translate revenue and expenses using average monthly exchange rates. The related translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in our consolidated balance sheet. Any foreign currency transaction gains or losses are included in our consolidated statement of income.
Use of Estimates	Our consolidated financial statements are prepared in accordance with GAAP, which require us to select accounting policies, including in certain cases industry-specific policies, and make estimates that affect the reported amount of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and contingent liabilities. Actual results could differ from these estimates. We believe that the judgments and related estimates for the following items are critical in the preparation of our consolidated financial statements: • film and television costs (see Note 4) • goodwill and intangible assets (see Note 11) In addition, the following accounting policy is specific to the industries in which we operate: • capitalization and amortization of film and television costs (see Note 4) Information on other accounting policies and methods that we use in the preparation of our consolidated financial statements are included, where applicable, in their respective footnotes that follow. Below is a discussion of accounting policies and methods used in our consolidated financial statements that are not presented within other footnotes.
Advertising Cost	Advertising costs are expensed as incurred.
Cash Equivalents	The carrying amounts of our cash equivalents approximate their fair values. Our cash equivalents consist primarily of money market funds and U.S. government obligations, as well as commercial paper and certificates of deposit with maturities of three months or less when purchased.
Derivative Financial Instruments	We use derivative financial instruments to manage our exposure to the risks associated with fluctuations in foreign exchange rates and interest rates. Our objective is to manage the financial and operational exposure arising from these risks by offsetting gains and losses on the underlying exposures with gains and losses on the derivatives used to economically hedge them. Our derivative financial instruments are recorded in our consolidated balance sheet at fair value. The impact of our derivative financial instruments on our consolidated financial statements was not material in any of the periods presented.
Fair Value Measurements	The accounting guidance related to fair value measurements establishes a hierarchy based on the types of inputs used for the various valuation techniques (market approach, income approach and cost approach). The levels of the hierarchy are described below. • Level 1: Values are determined using quoted market prices for identical financial instruments in an active market • Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable • Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation We use these levels of hierarchy to measure the fair value of certain financial instruments on a recurring basis, such as for investments; on a non-recurring basis, such as for acquisitions and impairment testing; for disclosure purposes, such as long-term debt; and for other applications, as discussed in their respective footnotes. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation and classification within the fair value hierarchy.
Revenue Recognition	Distribution Our Cable Networks segment generates distribution revenue from the distribution of our cable network programming to traditional and virtual multichannel video providers. Our Broadcast Television segment generates distribution revenue from the fees received under retransmission consent agreements and associated fees received from NBC-affiliated local broadcast television stations. Distribution revenue is accounted for as a license of functional intellectual property and is recognized as programming is provided on a monthly basis, generally under multiyear agreements. Monthly fees received under distribution agreements with multichannel video providers are generally based on the number of subscribers. Payment terms and conditions vary by contract type, although terms generally include payment within 30 to 60 days. Advertising Our Cable Networks and Broadcast Television segments generate advertising revenue from the sale of advertising on our cable and broadcast networks, our owned local broadcast television stations and various digital properties. We enter into advertising arrangements with customers and have determined that a contract exists once all terms and conditions are agreed upon, typically when the number of advertising units is specifically identified and the timing of airing is scheduled. Advertisements are generally aired or viewed within one year once all terms are agreed upon. Advertising revenue is recognized, net of agency commissions, in the period in which advertisements are aired or viewed and payment occurs thereafter, with payment generally required within 30 days. In some instances, we guarantee audience ratings for the advertisements. To the extent there is a shortfall in contracts where the ratings were guaranteed, a portion of the revenue is deferred until the shortfall is settled, typically by providing additional advertising units generally within one year of the original airing. Theatrical Our Filmed Entertainment segment generates theatrical revenue from the worldwide theatrical release of our produced and acquired films for exhibition in movie theaters. Theatrical revenue is affected by the timing, nature and number of films released in movie theaters and their acceptance by audiences. It is also affected by the number of exhibition screens, ticket prices, the percentage of ticket sale retention by the exhibitors and the popularity of competing films at the time our films are released. We recognize theatrical revenue as the films are viewed and exhibited in theaters and payment generally occurs within 30 days after exhibition. Content Licensing Our Cable Networks, Broadcast Television and Filmed Entertainment segments generate revenue from the licensing of our owned film and television content in the United States and internationally to cable, broadcast and premium networks and subscription video on demand services. Our content licensing agreements generally include fixed pricing and span multiple years. For example, following a film’s theatrical release, our Filmed Entertainment segment may license the exhibition rights of a film to different customers over multiple successive distribution windows. We recognize revenue when the content is delivered and available for use by the licensee. When the term of an existing agreement is renewed or extended, we recognize revenue at the later of when the content is available or when the renewal or extension period begins. Payment terms and conditions vary by contract type, although payments are generally collected over the license term. The amount of future revenue to be earned related to fixed pricing under existing agreements primarily relates to our Filmed Entertainment segment, which at any given time equals approximately 1 to 2 years of our annual Filmed Entertainment content licensing revenue. The majority of this revenue will be recognized within 2 years. This amount may fluctuate from period to period depending on the timing of the releases and the availability of content under existing agreements and may not represent the total content licensing revenue expected to be recognized as it does not include revenue from future agreements or from variable pricing or optional purchases under existing agreements. For our content licensing agreements that include variable pricing, such as pricing based on the number of subscribers to a subscription video on demand service sold by our customers, we generally recognize revenue as our customers sell to their subscribers. Home Entertainment Our Filmed Entertainment segment generates revenue from the sale of our produced and acquired films on standard-definition digital video discs and Blu-ray discs (together, “DVDs”) and through digital distribution services. Our Cable Networks and Broadcast Television networks also generate revenue from the sale of owned programming on DVDs and through digital distribution services, which is reported in other revenue. We generally recognize revenue from DVD sales, net of estimated returns and customer incentives, on the date that DVDs are delivered to and made available for sale by retailers. Payment terms generally include payment within 60 to 90 days from delivery to the retailer. Theme Parks Our Theme Parks segment generates revenue primarily from ticket sales and guest spending at our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. Guest spending includes in-park spending on food, beverages and merchandise. We recognize revenue from theme park ticket sales when the tickets are used, generally within a year from the date of purchase. For annual passes, we generally recognize revenue on a straight-line basis over the period the pass is available to be used. We recognize revenue from guest spending at the point of sale.
Film And Television Costs	We capitalize film and television production costs, including direct costs, production overhead, print costs, development costs and interest. We amortize capitalized film and television production costs, including acquired libraries, and accrue costs associated with participation and residual payments to programming and production expenses. We generally record the amortization and the accrued costs using the individual film forecast computation method, which amortizes the costs in the same ratio as the associated ultimate revenue. Estimates of ultimate revenue and total costs are based on anticipated release patterns, public acceptance and historical results for similar productions. Unamortized film and television production costs, including acquired libraries, are stated at the lower of unamortized cost or fair value. We do not capitalize costs related to the distribution of a film in movie theaters or the licensing or sale of a film or television production, which primarily include costs associated with marketing and distribution. In determining the method of amortization and estimated life of an acquired film or television library, we generally use the method and the life that most closely follow the undiscounted cash flows over the estimated life of the asset. When an event or a change in circumstance occurs that was known or knowable as of the balance sheet date and that indicates the fair value of a film is less than its unamortized costs, we determine the fair value of the film and record an impairment charge for the amount by which the unamortized capitalized costs exceed the film’s fair value. The estimated fair value of a production is based on Level 3 inputs that primarily use an analysis of future expected cash flows. Adjustments to capitalized film production costs were not material in any of the periods presented. We may enter into cofinancing arrangements with third parties to jointly finance or distribute certain of our film productions. Cofinancing arrangements can take various forms, but in most cases involve the grant of an economic interest in a film to an investor. The number of investors and the terms of these arrangements can vary, although investors generally assume the full risks and rewards for the portion of the film acquired in these arrangements. We account for the proceeds received from a third-party investor under these arrangements as a reduction to our capitalized film costs. Under these arrangements, the investor owns an undivided copyright interest in the film, and therefore in each period we record either a charge or a benefit to programming and production expenses to reflect the estimate of the third-party investor’s interest in the profit or loss of the film. The estimate of the third-party investor’s interest in the profit or loss of a film is determined using the ratio of actual revenue earned to date to the ultimate revenue expected to be recognized over the film’s useful life. We capitalize the costs of programming content that we license but do not own, including rights to multiyear, live-event sports programming, at the earlier of when payments are made for the programming or when the license period begins and the content is made available for use. We amortize capitalized programming costs as the associated programs are broadcast. We generally amortize multiyear, live-event sports programming rights using the ratio of the current period revenue to the estimated ultimate revenue or under the terms of the contract. Programming costs are recorded at the lower of unamortized cost or net realizable value on a program by program, package, channel or daypart basis. A daypart is an aggregation of programs broadcast during a particular time of day or programs of a similar type. Programming acquired by our Cable Networks segment is primarily tested on a channel basis for impairment, whereas programming acquired by our Broadcast Television segment is tested on a daypart basis. If we determine that the estimates of future cash flows are insufficient or if there is no plan to broadcast certain programming, we recognize an impairment charge to programming and production expenses.
Recent Accounting Pronouncements	Revenue Recognition In May 2014, the Financial Accounting Standards Board (“FASB”) updated the accounting guidance related to revenue recognition. The updated accounting guidance provides a single, contract-based revenue recognition model to help improve financial reporting by providing clearer guidance on when an entity should recognize revenue and by reducing the number of standards to which an entity has to refer. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the updated guidance on January 1, 2018 on a full retrospective basis, which required us to reflect the impact of the updated guidance for all periods presented. The adoption of the new standard did not have a material impact on our consolidated results of operations or financial position for any period presented. The updated guidance also requires additional disclosures regarding the nature, timing and uncertainty of our revenue transactions. See Note 3 for additional information. The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 32,997 $ (47 ) $ 32,950 Total costs and expenses $ 26,516 $ (43 ) $ 26,473 Operating income $ 6,481 $ (4 ) $ 6,477 Net income attributable to NBCUniversal $ 5,084 $ (4 ) $ 5,080 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 31,593 $ (195 ) $ 31,398 Total costs and expenses $ 26,171 $ (131 ) $ 26,040 Operating income $ 5,422 $ (64 ) $ 5,358 Net income attributable to NBCUniversal $ 4,235 $ (64 ) $ 4,171 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 11,673 $ 284 $ 11,957 Film and television costs $ 7,071 $ 11 $ 7,082 Other noncurrent assets, net $ 1,872 $ (68 ) $ 1,804 Total assets $ 71,073 $ 227 $ 71,300 Total current liabilities $ 9,602 $ 330 $ 9,932 Other noncurrent liabilities $ 4,109 $ 44 $ 4,153 Total equity $ 43,188 $ (147 ) $ 43,041 Total liabilities and equity $ 71,073 $ 227 $ 71,300 The adoption of the updated guidance impacted the timing of recognition for some of our revenue contracts, primarily for content licensing agreements. As a result of the adoption of the updated guidance, when the term of an existing content licensing agreement is renewed or extended, revenue is not recognized until the date when the renewal or extension period begins. Under the prior guidance, revenue for the content licensing renewal period was recognized on the date that the renewal was agreed to contractually. This change resulted in delayed revenue recognition for content licensing renewals or extensions in our Cable Networks, Broadcast Television and Filmed Entertainment segments. This change also impacted the timing of the related amortization of our film and television costs and participations and residuals expenses. The adoption of the updated guidance did not have a material impact on the results of operations or financial position for the reportable segments. Financial Assets and Financial Liabilities In January 2016, the FASB updated the accounting guidance related to the recognition and measurement of financial assets and financial liabilities. The updated accounting guidance, among other things, requires that all nonconsolidated equity investments, except those accounted for under the equity method, be measured at fair value and the changes in fair value be recognized in net income. On January 1, 2018, we adopted the updated guidance prospectively along with a related clarifying update and as a result, we recorded a $232 million cumulative effect adjustment to member's capital and accumulated other comprehensive income (loss). See Note 9 for additional information. Restricted Cash In November 2016, the FASB updated the accounting guidance related to restricted cash. The new standard requires that the statement of cash flows present the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents, and a reconciliation of that total to amounts presented on the balance sheet. We adopted the updated guidance on January 1, 2018 and as required applied the retrospective transition method. The adoption did not have a material impact for any period presented. Leases In February 2016, the FASB updated the accounting guidance related to leases. The updated accounting guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases with the exception of short-term leases. The asset and liability are initially measured based on the present value of committed lease payments. For a lessee, the recognition, measurement and presentation of expenses and cash flows arising from a lease do not significantly change from previous guidance. For a lessor, the accounting applied is also largely unchanged from previous guidance. We will adopt the updated accounting guidance in the first quarter of 2019 and prior periods will not be adjusted. We are currently in the process of determining the impact that the updated accounting will have on our consolidated financial statements. See Note 14 for a summary of our undiscounted minimum rental commitments under operating leases as of December 31, 2018.
Investments	Equity Method We use the equity method to account for investments in which we have the ability to exercise significant influence over the investee’s operating and financial policies or in which we hold a significant partnership or limited liability company interest. Equity method investments are recorded at cost and are adjusted to recognize (1) our proportionate share of the investee’s net income or loss after the date of investment, (2) amortization of the recorded investment that exceeds our share of the book value of the investee’s net assets, (3) additional contributions made and dividends received, and (4) impairments resulting from other-than-temporary declines in fair value. For some investments, we record our share of the investee’s net income or loss one quarter in arrears due to the timing of our receipt of such information. Gains or losses on the sale of equity method investments are recorded to other income (loss), net. If an equity method investee were to issue additional securities that would change our proportionate share of the entity, we would recognize the change, if any, as a gain or loss to other income (loss), net. Marketable Equity Securities We classify publicly traded investments with readily determinable fair values that are not accounted for under the equity method as marketable equity securities. Marketable equity securities are recorded at cost and adjusted to fair value at each reporting period. The changes in fair value between measurement dates are recorded in realized and unrealized gains (losses) on equity securities, net. The fair values of our marketable equity securities are based on Level 1 inputs that use quoted market prices. Nonmarketable Equity Securities We classify investments without readily determinable fair values that are not accounted for under the equity method as nonmarketable equity securities. The accounting guidance requires nonmarketable equity securities to be recorded at cost and adjusted to fair value at each reporting period. However, the guidance allows for a measurement alternative, which is to record the investments at cost, less impairment, if any, and subsequently adjust for observable price changes of identical or similar investments of the same issuer. We apply this measurement alternative to our nonmarketable equity securities. When an observable event occurs, we estimate the fair values of our nonmarketable equity securities based on Level 2 inputs that are derived from observable price changes of similar securities adjusted for insignificant differences in rights and obligations. The changes in value are recorded in realized and unrealized gains (losses) on equity securities, net.
Impairment Testing of Investments	Impairment Testing of Investments We review our investment portfolio, other than our marketable equity securities, each reporting period to determine whether there are identified events or circumstances that would indicate there is a decline in the fair value. For our nonpublic investments, if there are no identified events or circumstances that would have a significant adverse effect on the fair value of the investment, then the fair value is not estimated. For our equity method investments and held to maturity investments, if an investment is deemed to have experienced an other-than-temporary decline below its cost basis, we reduce the carrying amount of the investment to its quoted or estimated fair value, as applicable, and establish a new cost basis for the investment. For our nonmarketable equity securities, we record the impairment to realized and unrealized gains (losses) on equity securities, net. For our equity method investments and our held to maturity investments, we record the impairment to other income (loss), net.
Property and Equipment	Property and equipment are stated at cost. We capitalize improvements that extend asset lives and expense repairs and maintenance costs as incurred. We record depreciation using the straight-line method over the asset’s estimated useful life. For assets that are sold or retired, we remove the applicable cost and accumulated depreciation and, unless the gain or loss on disposition is presented separately, we recognize it as a component of depreciation expense. We evaluate the recoverability of our property and equipment whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of depreciation expense.
Goodwill	Goodwill is calculated as the excess of the consideration transferred over the identifiable net assets acquired in a business combination and represents the future economic benefits expected to arise from anticipated synergies and intangible assets acquired that do not qualify for separate recognition, including assembled workforce, noncontractual relationships and other agreements. We assess the recoverability of our goodwill annually, or more frequently whenever events or substantive changes in circumstances indicate that the carrying amount of a reporting unit may exceed its fair value. We test goodwill for impairment at the reporting unit level. To determine our reporting units, we evaluate the components one level below the segment level and we aggregate the components if they have similar economic characteristics. As a result of this assessment, our reporting units are generally the same as our four reportable segments. We evaluate the determination of our reporting units used to test for impairment periodically or whenever events or substantive changes in circumstances occur. The assessment of recoverability may first consider qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. The quantitative assessment considers whether the carrying amount of a reporting unit exceeds its fair value, in which case an impairment charge is recorded to the extent the reporting unit’s carrying value exceeds its fair value. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any impairment charges in any of the periods presented.
Indefinite-Lived Intangible Assets	Indefinite-lived intangible assets consist of trade names and FCC licenses. We assess the recoverability of our indefinite-lived intangible assets annually, or more frequently whenever events or substantive changes in circumstances indicate that the assets might be impaired. We evaluate the unit of account used to test for impairment of our indefinite-lived intangible assets periodically or whenever events or substantive changes in circumstances occur to ensure impairment testing is performed at an appropriate level. The assessment of recoverability may first consider qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount. A quantitative assessment is performed if the qualitative assessment results in a more-likely-than-not determination or if a qualitative assessment is not performed. When performing a quantitative assessment, we estimate the fair value of our indefinite-lived intangible assets primarily based on a discounted cash flow analysis that involves significant judgment. When analyzing the fair values indicated under the discounted cash flow models, we also consider multiples of Adjusted EBITDA generated by the underlying assets, current market transactions and profitability information. If the fair value of our indefinite-lived intangible assets were less than the carrying amount, we would recognize an impairment charge for the difference between the estimated fair value and the carrying value of the assets. Unless presented separately, the impairment charge is included as a component of amortization expense. We did not recognize any material impairment charges in any of the periods presented.
Finite-Lived Intangible Assets	Finite-lived intangible assets are subject to amortization and consist primarily of customer relationships acquired in business combinations, software, and intellectual property rights. Our finite-lived intangible assets are amortized primarily on a straight-line basis over their estimated useful life or the term of the associated agreement. We capitalize direct development costs associated with internal-use software, including external direct costs of material and services and payroll costs for employees devoting time to these software projects. We also capitalize costs associated with the purchase of software licenses. We generally amortize them on a straight-line basis over a period not to exceed five years . We expense maintenance and training costs, as well as costs incurred during the preliminary stage of a project, as they are incurred. We capitalize initial operating system software costs and amortize them over the life of the associated hardware. We evaluate the recoverability of our finite-lived intangible assets whenever events or substantive changes in circumstances indicate that the carrying amount may not be recoverable. The evaluation is based on the cash flows generated by the underlying asset groups, including estimated future operating results, trends or other determinants of fair value. If the total of the expected future undiscounted cash flows were less than the carrying amount of the asset group, we would recognize an impairment charge to the extent the carrying amount of the asset group exceeded its estimated fair value. Unless presented separately, the impairment charge is included as a component of amortization expense.
Postretirement and Pension Benefits	We sponsor various nonqualified defined benefit pension plans for domestic employees. Since the future benefits have been frozen since the beginning of 2013, we did not recognize service costs related to our pension plans in any of the periods presented. The benefits expense we recognized for our defined benefit plans was not material for any period presented. In addition to the defined benefit plans we sponsor, we are also obligated to reimburse The General Electric Company (“GE”) for future benefit payments to those participants who were vested in the supplemental pension plan sponsored by GE at the time of Comcast’s acquisition of NBCUniversal. The plan is unfunded and substantially all of our postretirement benefit obligations are recorded to noncurrent liabilities. The expense we recognize for the plan is determined using certain assumptions, including the discount rate. The benefits expense we recognized for the plan was not material in any of the periods presented.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting Information [Line Items]
Financial Data by Business Segment	We use Adjusted EBITDA to evaluate the profitability of our operating segments, and the components of net income attributable to Comcast Corporation excluded from Adjusted EBITDA are not separately evaluated. To be consistent with our current management reporting presentation, certain 2018, 2017 and 2016 operating results were reclassified related to certain NBCUniversal businesses now presented in the Sky segment. We do not present a measure of total assets for our reportable business segments as this information is not used by management to allocate resources and capital. Our financial data by business segment is presented in the tables below. (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2018 Cable Communications $ 55,143 $ 22,447 $ 8,264 $ 7,716 $ 1,282 NBCUniversal Cable Networks (a) 11,773 4,428 738 42 23 Broadcast Television (a) 11,439 1,657 146 204 81 Filmed Entertainment 7,152 734 145 35 25 Theme Parks 5,683 2,455 660 1,143 173 Headquarters and Other (b) 63 (680 ) 419 306 146 Eliminations (a)(c) (349 ) 4 — — — NBCUniversal 35,761 8,598 2,108 1,730 448 Sky 4,587 692 539 222 137 Corporate and Other (d) 1,403 (1,545 ) 106 106 68 Eliminations (a)(c) (2,387 ) (27 ) — — — Comcast Consolidated $ 94,507 $ 30,165 $ 11,017 $ 9,774 $ 1,935 (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2017 Cable Communications $ 53,070 $ 21,068 $ 8,006 $ 7,952 $ 1,241 NBCUniversal Cable Networks 10,497 4,053 755 33 19 Broadcast Television 9,563 1,251 133 180 22 Filmed Entertainment 7,595 1,276 109 58 23 Theme Parks 5,443 2,384 648 960 78 Headquarters and Other (b) 45 (741 ) 396 271 153 Eliminations (c) (307 ) (5 ) — — — NBCUniversal 32,836 8,218 2,041 1,502 295 Corporate and Other (d) 1,193 (1,372 ) 83 96 69 Eliminations (c) (2,070 ) 42 — — — Comcast Consolidated $ 85,029 $ 27,956 $ 10,130 $ 9,550 $ 1,605 (in millions) Revenue Adjusted EBITDA (e) Depreciation and Capital Cash Paid for 2016 Cable Communications $ 50,577 $ 20,014 $ 7,538 $ 7,596 $ 1,243 NBCUniversal Cable Networks (a) 10,324 3,681 745 32 20 Broadcast Television (a) 10,085 1,293 125 153 19 Filmed Entertainment 6,229 662 47 33 16 Theme Parks 4,946 2,190 512 922 72 Headquarters and Other (b) 20 (699 ) 376 312 156 Eliminations (a)(c) (328 ) 11 — — — NBCUniversal 31,276 7,138 1,805 1,452 283 Corporate and Other (d) 886 (849 ) 83 87 26 Eliminations (a)(c) (2,003 ) (46 ) — — — Comcast Consolidated $ 80,736 $ 26,257 $ 9,426 $ 9,135 $ 1,552 (a) The revenue and operating costs and expenses associated with our broadcast of the 2018 PyeongChang Olympics and the 2016 Rio Olympics were reported in our Cable Networks and Broadcast Television segments. The revenue and operating costs and expenses associated with our broadcast of the 2018 Super Bowl were reported in our Broadcast Television segment. Included in Eliminations are transactions relating to these events that our Broadcast Television and Cable Networks segments enter into with our other segments. (b) NBCUniversal Headquarters and Other activities include costs associated with overhead, allocations, personnel and headquarter initiatives. (c) Included in Eliminations are transactions that our segments enter into with one another. The most common types of transactions are the following: • our Cable Networks segment generates revenue by selling programming to our Cable Communications segment, which represents a substantial majority of the revenue elimination amount • our Broadcast Television segment generates revenue from the fees received under retransmission consent agreements with our Cable Communications segment • our Cable Communications segment generates revenue by selling advertising and by selling the use of satellite feeds to our Cable Networks segment • our Cable Networks and Broadcast Television segments generate revenue by selling advertising to our Cable Communications segment • our Filmed Entertainment and Broadcast Television segments generate revenue by licensing content to our Cable Networks segment; for segment reporting, this revenue is recognized as the programming rights asset for the licensed content is amortized based on third-party revenue • our Filmed Entertainment, Cable Networks and Broadcast Television segments generate revenue by licensing content to our Sky segment (d) Corporate and Other activities include costs associated with overhead and personnel, revenue and expenses associated with other business development initiatives, including our wireless phone service, and the operations of Comcast Spectacor, which owns the Philadelphia Flyers and the Wells Fargo Center arena in Philadelphia, Pennsylvania. (e) We use Adjusted EBITDA as the measure of profit or loss for our operating segments. Adjusted EBITDA is defined as net income attributable to Comcast Corporation before net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock, income tax benefit (expense), investment and other income (loss), net, interest expense, depreciation and amortization expense, and other operating gains and losses (such as impairment charges related to fixed and intangible assets and gains or losses on the sale of long-lived assets), if any. From time to time we may exclude from Adjusted EBITDA the impact of certain events, gains, losses or other charges (such as significant legal settlements) that affect the period-to-period comparability of our operating performance.
Reconciliation of Adjusted EBITDA from Segments to Consolidated	Our reconciliation of the aggregate amount of Adjusted EBITDA for our reportable segments to consolidated income before income taxes is presented in the table below. Year ended December 31 (in millions) 2018 2017 2016 Adjusted EBITDA $ 30,165 $ 27,956 $ 26,257 Adjustment for legal settlement (125 ) (250 ) — Adjustment for Sky transaction-related costs (355 ) — — Depreciation (8,281 ) (7,914 ) (7,464 ) Amortization (2,736 ) (2,216 ) (1,962 ) Other operating gains 341 442 — Interest expense (3,542 ) (3,086 ) (2,942 ) Investment and other income (loss), net (225 ) 421 437 Income before income taxes $ 15,242 $ 15,353 $ 14,326
NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Financial Data by Business Segment	Our Cable Networks segment consists primarily of a diversified portfolio of cable television networks. Our Cable Networks segment is comprised of our national cable networks that provide a variety of entertainment, news and information, and sports content; our regional sports and news networks; our international cable networks; our cable television studio production operations; and our various digital properties. Our Broadcast Television segment consists primarily of the NBC and Telemundo broadcast networks, our NBC and Telemundo owned local broadcast television stations, the NBC Universo national cable network, our broadcast television studio production operations, and our various digital properties. Our Filmed Entertainment segment primarily produces, acquires, markets and distributes filmed entertainment worldwide. Our films are produced primarily under the Universal Pictures, Illumination, DreamWorks Animation and Focus Features names. Our Theme Parks segment consists primarily of our Universal theme parks in Orlando, Florida; Hollywood, California; and Osaka, Japan. In addition, along with a consortium of Chinese state-owned companies, we are developing a Universal theme park and resort in Beijing, China. We use Adjusted EBITDA to evaluate the profitability of our operating segments, and the components of net income attributable to NBCUniversal excluded from Adjusted EBITDA are not separately evaluated. To be consistent with our current management reporting presentation, certain 2018, 2017 and 2016 operating results were reclassified related to certain NBCUniversal businesses now presented in Headquarters and Other. We do not present a measure of total assets for our reportable business segments as this information is not used by management to allocate resources and capital. Our financial data by business segment is presented in the tables below. (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2018 Cable Networks (a) $ 11,773 $ 4,428 $ 738 $ 42 $ 23 Broadcast Television (a) 11,439 1,657 146 204 81 Filmed Entertainment 7,152 734 145 35 25 Theme Parks 5,683 2,455 660 1,143 173 Headquarters and Other (b) 212 (645 ) 419 306 146 Eliminations (a)(c) (364 ) 4 — — — Total $ 35,895 $ 8,633 $ 2,108 $ 1,730 $ 448 (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2017 Cable Networks $ 10,497 $ 4,053 $ 755 $ 33 $ 19 Broadcast Television 9,563 1,251 133 180 22 Filmed Entertainment 7,595 1,276 109 58 23 Theme Parks 5,443 2,384 648 960 78 Headquarters and Other (b) 179 (779 ) 396 271 153 Eliminations (c) (327 ) (4 ) — — — Total $ 32,950 $ 8,181 $ 2,041 $ 1,502 $ 295 (in millions) Revenue Adjusted EBITDA (d) Depreciation and Capital Cash Paid for 2016 Cable Networks (a) $ 10,324 $ 3,681 $ 745 $ 32 $ 20 Broadcast Television (a) 10,085 1,293 125 153 19 Filmed Entertainment 6,229 662 47 33 16 Theme Parks 4,946 2,190 512 922 72 Headquarters and Other (b) 157 (674 ) 376 312 156 Eliminations (a)(c) (343 ) 11 — — — Total $ 31,398 $ 7,163 $ 1,805 $ 1,452 $ 283 (a) The revenue and operating costs and expenses associated with our broadcast of the 2018 PyeongChang Olympics and the 2016 Rio Olympics were reported in our Cable Networks and Broadcast Television segments. The revenue and operating costs and expenses associated with our broadcast of the 2018 Super Bowl were reported in our Broadcast Television segment. Included in Eliminations are transactions relating to these events that our Broadcast Television and Cable Networks segments enter into with our other segments. (b) Headquarters and Other activities include costs associated with overhead, allocations, personnel and headquarter initiatives. (c) Eliminations are transactions that our segments enter into with one another, which consisted primarily of the licensing of film and television content from our Filmed Entertainment and Broadcast Television segments to our Cable Networks segment; for segment reporting, revenue is recognized as the programming rights asset for the licensed content is amortized based on third-party revenue. (d) We use Adjusted EBITDA as the measure of profit or loss for our operating segments. Adjusted EBITDA is defined as net income attributable to NBCUniversal before net (income) loss attributable to noncontrolling interests, income tax expense, investment and other income (loss), net, interest expense, depreciation and amortization expense, and other operating gains and losses (such as impairment charges related to fixed and intangible assets and gains or losses on the sale of long-lived assets), if any. From time to time we may exclude from Adjusted EBITDA the impact of certain events, gains, losses or other charges (such as significant legal settlements) that affect the period-to-period comparability of our operating performance.
Reconciliation of Adjusted EBITDA from Segments to Consolidated	Our reconciliation of the aggregate amount of Adjusted EBITDA for our reportable segments to consolidated income before income taxes is presented in the table below. Year ended December 31 (in millions) 2018 2017 2016 Adjusted EBITDA $ 8,633 $ 8,181 $ 7,163 Depreciation (1,001 ) (994 ) (861 ) Amortization (1,107 ) (1,047 ) (944 ) Other operating gains 141 337 — Interest expense (489 ) (727 ) (595 ) Investment and other income (loss), net (521 ) (144 ) 24 Income before income taxes $ 5,656 $ 5,606 $ 4,787

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue [Line Items]
Schedule of receivables, net	December 31 (in millions) 2018 2017 Receivables, gross $ 11,456 $ 9,122 Less: Allowance for doubtful accounts 352 288 Receivables, net $ 11,104 $ 8,834
NBCUniversal Media LLC [Member]
Revenue [Line Items]
Schedule of receivables, net	December 31 (in millions) 2018 2017 Receivables, gross $ 7,392 $ 7,055 Less: Allowance for doubtful accounts 99 88 Receivables, net $ 7,293 $ 6,967
Accounting Standards Update 2014-09 [Member]
Revenue [Line Items]
Disaggregation of revenue	Year ended December 31 (in millions) 2018 2017 2016 Residential: High-speed internet $ 17,144 $ 15,681 $ 14,421 Video 22,455 22,874 22,204 Voice 3,960 4,090 4,159 Business services 7,129 6,437 5,705 Advertising 2,795 2,450 2,626 Other 1,660 1,538 1,462 Total Cable Communications (a) 55,143 53,070 50,577 Distribution 6,826 6,081 5,978 Advertising 3,587 3,359 3,530 Content licensing and other 1,360 1,057 816 Total Cable Networks 11,773 10,497 10,324 Advertising 7,010 5,654 6,834 Content licensing 2,182 2,114 1,837 Distribution and other 2,247 1,795 1,414 Total Broadcast Television 11,439 9,563 10,085 Theatrical 2,111 2,192 1,560 Content licensing 2,899 2,956 2,518 Home entertainment 1,048 1,287 1,182 Other 1,094 1,160 969 Total Filmed Entertainment 7,152 7,595 6,229 Total Theme Parks 5,683 5,443 4,946 Headquarters and Other 63 45 20 Eliminations (b) (349 ) (307 ) (328 ) Total NBCUniversal 35,761 32,836 31,276 Direct-to-consumer 3,632 — — Content 304 — — Advertising 651 — — Total Sky 4,587 — — Corporate and Other 1,403 1,193 886 Eliminations (b) (2,387 ) (2,070 ) (2,003 ) Total revenue $ 94,507 $ 85,029 $ 80,736 (a) For 2018, 2017 and 2016, 2.7% , 2.8% and 2.9% , respectively, of Cable Communications segment revenue was derived from franchise and other regulatory fees. (b) Included in Eliminations are transactions that our segments enter into with one another. See Note 2 for a description of these transactions. We operate primarily in the United States, but also in select international markets primarily in Europe and Asia. The table below summarizes revenue by geographic location. Year ended December 31 (in millions) 2018 2017 2016 United States $ 82,233 $ 77,246 $ 74,212 Foreign 12,274 7,783 6,524 Total revenue $ 94,507 $ 85,029 $ 80,736
Other balance sheet accounts	December 31 (in millions) 2018 2017 Noncurrent receivables (included in other noncurrent assets, net) $ 1,399 $ 1,184 Contract acquisition and fulfillment costs (included in other noncurrent assets, net) $ 991 $ 922 Noncurrent deferred revenue (included in other noncurrent liabilities) $ 650 $ 497
Accounting Standards Update 2014-09 [Member] | NBCUniversal Media LLC [Member]
Revenue [Line Items]
Disaggregation of revenue	Year ended December 31 (in millions) 2018 2017 2016 Distribution $ 6,826 $ 6,081 $ 5,978 Advertising 3,587 3,359 3,530 Content licensing and other 1,360 1,057 816 Total Cable Networks 11,773 10,497 10,324 Advertising 7,010 5,654 6,834 Content licensing 2,182 2,114 1,837 Distribution and other 2,247 1,795 1,414 Total Broadcast Television 11,439 9,563 10,085 Theatrical 2,111 2,192 1,560 Content licensing 2,899 2,956 2,518 Home entertainment 1,048 1,287 1,182 Other 1,094 1,160 969 Total Filmed Entertainment 7,152 7,595 6,229 Total Theme Parks 5,683 5,443 4,946 Headquarters and Other 212 179 157 Eliminations (a) (364 ) (327 ) (343 ) Total NBCUniversal $ 35,895 $ 32,950 $ 31,398 (a) Included in Eliminations are transactions that our segments enter into with one another. See Note 2 for a description of these transactions. We operate primarily in the United States, but also in select international markets primarily in Europe and Asia. The table below summarizes revenue by geographic location. Year ended December 31 (in millions) 2018 2017 2016 United States $ 28,309 $ 25,303 $ 24,907 Foreign 7,586 7,647 6,491 Total revenue $ 35,895 $ 32,950 $ 31,398
Other balance sheet accounts	December 31 (in millions) 2018 2017 Noncurrent receivables (included in other noncurrent assets, net) $ 1,180 $ 1,093 Noncurrent deferred revenue (included in other noncurrent liabilities) $ 481 $ 392

Programming and Production Co_2

Programming and Production Costs (Tables)	12 Months Ended
	Dec. 31, 2018
Film And Television Cost [Line Items]
Film and Television Costs	December 31 (in millions) 2018 2017 Film Costs: Released, less amortization $ 1,600 $ 1,734 Completed, not released 144 50 In production and in development 1,063 1,149 2,807 2,933 Television Costs: Released, less amortization 2,289 2,260 In production and in development 953 818 3,242 3,078 Programming rights, less amortization 5,534 2,689 11,583 8,700 Less: Current portion of programming rights 3,746 1,613 Film and television costs $ 7,837 $ 7,087
NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Film and Television Costs	December 31 (in millions) 2018 2017 Film Costs: Released, less amortization $ 1,600 $ 1,734 Completed, not released 144 50 In production and in development 1,063 1,149 2,807 2,933 Television Costs: Released, less amortization 2,161 2,260 In production and in development 953 818 3,114 3,078 Programming rights, less amortization 2,694 2,677 8,615 8,688 Less: Current portion of programming rights 1,323 1,606 Film and television costs $ 7,292 $ 7,082

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Taxes [Line Items]
Schedule for the components of income tax expense	Components of Income Tax Expense (Benefit) Year ended December 31 (in millions) 2018 2017 2016 Current Expense (Benefit): Federal $ 2,026 $ 2,411 $ 3,190 State 639 277 480 Foreign 425 389 194 3,090 3,077 3,864 Deferred Expense (Benefit): Federal 546 (10,651 ) 1,183 State (167 ) 11 153 Foreign (89 ) (6 ) 98 290 (10,646 ) 1,434 Income tax expense (benefit) $ 3,380 $ (7,569 ) $ 5,298
Schedule of items that effect income tax expense	Our income tax expense (benefit) differs from the federal statutory amount because of the effect of the items detailed in the table below. Year ended December 31 (in millions) 2018 2017 2016 Federal tax at statutory rate $ 3,201 $ 5,374 $ 5,014 State income taxes, net of federal benefit 212 299 373 Foreign income taxed at different rates 147 70 65 Nontaxable income attributable to noncontrolling interests (20 ) (45 ) (128 ) Adjustments to uncertain and effectively settled tax positions, net 144 (62 ) 24 Accrued interest on uncertain and effectively settled tax positions, net 29 3 17 Excess tax benefits recognized on share-based compensation (75 ) (297 ) — Federal tax legislation (120 ) (12,682 ) — Other (138 ) (229 ) (67 ) Income tax expense (benefit) $ 3,380 $ (7,569 ) $ 5,298
Schedule of the components of net deferred tax liability	Components of Net Deferred Tax Liability December 31 (in millions) 2018 2017 Deferred Tax Assets: Net operating loss carryforwards $ 1,926 $ 481 Nondeductible accruals and other 2,656 2,092 Less: Valuation allowance 632 377 3,950 2,196 Deferred Tax Liabilities: Differences between book and tax basis of property and equipment and intangible assets 29,139 25,223 Differences between book and tax basis of investments 491 466 Differences between book and tax basis of long-term debt 604 673 Differences between book and tax basis of foreign subsidiaries and undistributed foreign earnings 85 39 30,319 26,401 Net deferred tax liability $ 26,369 $ 24,205
Reconciliation of unrecognized tax benefits	Reconciliation of Unrecognized Tax Benefits (in millions) 2018 2017 2016 Gross unrecognized tax benefits, January 1 $ 1,497 $ 1,443 $ 1,441 Additions based on tax positions related to the current year 229 121 74 Additions based on tax positions related to prior years 125 319 72 Additions from acquired subsidiaries 130 — 13 Reductions for tax positions of prior years (346 ) (251 ) (66 ) Reductions due to expiration of statutes of limitations (75 ) (70 ) (44 ) Settlements with tax authorities (17 ) (65 ) (47 ) Gross unrecognized tax benefits, December 31 1,543 1,497 1,443 Positions paid (531 ) (688 ) (340 ) Liability for uncertain tax positions $ 1,012 $ 809 $ 1,103
NBCUniversal Media LLC [Member]
Income Taxes [Line Items]
Schedule for the components of income tax expense	Components of Income Tax Expense Year ended December 31 (in millions) 2018 2017 2016 Foreign Current income tax expense $ 230 $ 201 $ 38 Deferred income tax expense (31 ) (7 ) 96 Withholding tax expense 163 187 158 U.S. domestic tax expense (11 ) 11 13 Income tax expense $ 351 $ 392 $ 305

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Computation of diluted EPS	Computation of Diluted EPS 2018 2017 2016 Year ended December 31 Net Income Shares Per Share Net Income Shares Per Share Net Income Shares Per Share Basic EPS attributable to Comcast Corporation shareholders $ 11,731 4,584 $ 2.56 $ 22,735 4,708 $ 4.83 $ 8,678 4,819 $ 1.80 Effect of dilutive securities: Assumed exercise or issuance of shares relating to stock plans 56 78 56 Diluted EPS attributable to Comcast Corporation shareholders $ 11,731 4,640 $ 2.53 $ 22,735 4,786 $ 4.75 $ 8,678 4,875 $ 1.78

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Instrument [Line Items]
Schedule of Long-Term Debt	Long-Term Debt Outstanding December 31 (in millions) Weighted-Average 2018 2017 Commercial paper 2.86 % $ 675 $ 903 Revolving bank credit facilities (b) 1.13 % 606 — Term loans (a) 1.85 % 13,268 3,880 Senior notes with maturities of 5 years or less, at face value (b) 3.48 % 26,331 15,680 Senior notes with maturities between 5 and 10 years, at face value (b) 3.64 % 26,727 13,277 Senior notes with maturities greater than 10 years, at face value (b)(c) 4.68 % 45,030 31,838 Other, including capital lease obligations — 808 921 Debt issuance costs, premiums, discounts, fair value adjustments for acquisition accounting and hedged positions, net (d) — (1,702 ) (1,943 ) Total debt 3.77 % (d) 111,743 64,556 Less: Current portion 4,398 5,134 Long-term debt $ 107,345 $ 59,422 (a) Term loans consist of the following, with foreign currency denominated borrowings translated using the exchange rates as of each date: • Comcast: borrowings associated with the Sky transaction of £5.6 billion as of December 31, 2018 (see Note 8) • Universal Studios Japan: ¥390 billion and ¥435 billion as of December 31, 2018 and 2017 , respectively • Universal Beijing Resort: ¥4 billion RMB as of December 31, 2018 (see Note 8) (b) The December 31, 2018 amounts include an aggregate of approximately $10.7 billion of Sky debt consolidated by Comcast. The Sky debt as of December 31, 2018 included $3.2 billion of senior notes, €4.9 billion of senior notes and £1.1 billion of senior notes that will mature between 2019 and 2035. The Sky senior notes were recorded at fair value as of October 9, 2018. (c) The December 31, 2018 and 2017 amounts include £625 million of 5.50% notes due 2029. (d) Includes the effects of our derivative financial instruments.
Debt Maturities	Principal Maturities of Debt (in millions) 2019 $ 4,413 2020 $ 7,961 2021 $ 11,548 2022 $ 8,741 2023 $ 7,818 Thereafter $ 72,964
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Schedule of Long-Term Debt	Long-Term Debt Outstanding December 31 (in millions) Weighted-Average Interest Rate as of December 31, 2018 2018 2017 Term loans (a) 1.30 % $ 4,122 $ 3,860 Senior notes with maturities of 5 years or less, at face value 4.39 % 5,000 4,000 Senior notes with maturities between 5 and 10 years, at face value — — 1,000 Senior notes with maturities greater than 10 years, at face value 5.50 % 2,759 2,759 Notes due 2049 to Comcast 4.00 % 610 610 Other, including capital lease obligations — 427 276 Debt issuance costs, premiums and discounts, net — (36 ) (32 ) Total debt 3.58 % 12,882 12,473 Less: Current portion 151 198 Long-term debt $ 12,731 $ 12,275 (a) Term loans consist of the following, with foreign currency denominated borrowings translated using the exchange rates as of each date: • Universal Studios Japan: ¥390 billion and ¥435 billion as of December 31, 2018 and 2017 , respectively • Universal Beijing Resort:
Debt Maturities	Principal Maturities of Debt (in millions) 2019 $ 153 2020 $ 2,280 2021 $ 2,365 2022 $ 2,922 2023 $ 1,012 Thereafter $ 4,186

Significant Transactions (Table

Significant Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Business Acquisition [Line Items]
Allocation of Purchase Price	The table below presents the preliminary allocation of the all-cash purchase price of £30.2 billion , or $39.4 billion , to the assets and liabilities of Sky as a result of the transaction. Preliminary Allocation of Purchase Price (in millions) Consideration transferred $ 39,387 Preliminary allocation of purchase price Cash $ 1,283 Accounts receivable and other current assets 2,405 Film and television costs (See Note 4) 2,526 Property and equipment (See Note 11) 3,386 Intangible assets (See Note 12) 20,628 Accounts payable, accrued liabilities and other current liabilities (5,791 ) Long-term debt (See Note 7) (11,215 ) Deferred tax assets (liabilities), net (See Note 5) (1,903 ) Other noncurrent assets and (liabilities), net (1,809 ) Fair value of identifiable net assets acquired 9,510 Goodwill (See Note 12) $ 29,877
Amounts Related to Expenses Included in Consolidated Statement of Operations	The table below presents the amounts related to these expenses included in our consolidated statement of income. (in millions) Year ended December 31, 2018 Other operating and administrative expenses $ 339 Interest expense $ 63
Unaudited Actual and Pro Forma Information	The following unaudited pro forma information has been presented as if the Sky transaction occurred on January 1, 2017. This information is based on historical results of operations, adjusted for allocation of purchase price and other acquisition accounting adjustments, and is not necessarily indicative of what the results would have been had we operated the business since January 1, 2017. For pro forma purposes, 2018 earnings were adjusted to exclude the acquisition-related costs noted above, and 2017 earnings were adjusted to include these costs. No pro forma adjustments have been made for cost savings or synergies that have been or may be achieved by the combined businesses. Year ended December 31 (in millions, except per share data) 2018 2017 Revenue $ 109,518 $ 102,971 Net income attributable to Comcast Corporation $ 11,365 $ 22,308 Basic earnings per common share attributable to Comcast Corporation shareholders $ 2.48 $ 4.74 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 2.45 $ 4.65

Recent Accounting Pronounceme_3

Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue From Contract With Customer Financial Statement Impact	The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 84,526 $ 503 $ 85,029 Total costs and expenses $ 66,539 $ 472 $ 67,011 Operating income $ 17,987 $ 31 $ 18,018 Net income attributable to Comcast Corporation $ 22,714 $ 21 $ 22,735 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 80,403 $ 333 $ 80,736 Total costs and expenses $ 63,544 $ 361 $ 63,905 Operating income $ 16,859 $ (28 ) $ 16,831 Net income attributable to Comcast Corporation $ 8,695 $ (17 ) $ 8,678 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 16,060 $ 283 $ 16,343 Film and television costs $ 7,076 $ 11 $ 7,087 Other intangible assets, net $ 18,779 $ (646 ) $ 18,133 Other noncurrent assets, net $ 3,489 $ 865 $ 4,354 Total assets $ 186,949 $ 513 $ 187,462 Total current liabilities $ 21,561 $ 432 $ 21,993 Deferred income taxes $ 24,256 $ 3 $ 24,259 Other noncurrent liabilities $ 10,904 $ 68 $ 10,972 Total equity $ 69,449 $ 10 $ 69,459 Total liabilities and equity $ 186,949 $ 513 $ 187,462 The tables below present the effects these changes had on our Cable Communications segment revenue, operating costs and expenses, and depreciation and amortization expense as a result of the adoption of updated guidance for the prior year periods. Previously reported amounts are based on amounts previously presented in the segment information footnote. Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 14,769 $ 912 $ 15,681 Video 23,129 (255 ) 22,874 Voice 3,391 699 4,090 Business services 6,216 221 6,437 Advertising 2,257 193 2,450 Other 2,757 (1,219 ) 1,538 Total Cable Communications revenue $ 52,519 $ 551 $ 53,070 Operating costs and expenses $ 31,349 $ 653 $ 32,002 Depreciation and amortization expense $ 8,143 $ (137 ) $ 8,006 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Residential: High-speed internet $ 13,532 $ 889 $ 14,421 Video 22,357 (153 ) 22,204 Voice 3,540 619 4,159 Business services 5,514 191 5,705 Advertising 2,476 150 2,626 Other 2,629 (1,167 ) 1,462 Total Cable Communications revenue $ 50,048 $ 529 $ 50,577 Operating costs and expenses $ 29,939 $ 624 $ 30,563 Depreciation and amortization expense $ 7,670 $ (132 ) $ 7,538
NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue From Contract With Customer Financial Statement Impact	The tables below present the effects on our consolidated statement of income and balance sheet for the prior year periods presented. Consolidated Statement of Income Year ended December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 32,997 $ (47 ) $ 32,950 Total costs and expenses $ 26,516 $ (43 ) $ 26,473 Operating income $ 6,481 $ (4 ) $ 6,477 Net income attributable to NBCUniversal $ 5,084 $ (4 ) $ 5,080 Year ended December 31, 2016 (in millions) Previously Reported Effects of Adoption As Adjusted Revenue $ 31,593 $ (195 ) $ 31,398 Total costs and expenses $ 26,171 $ (131 ) $ 26,040 Operating income $ 5,422 $ (64 ) $ 5,358 Net income attributable to NBCUniversal $ 4,235 $ (64 ) $ 4,171 Consolidated Balance Sheet December 31, 2017 (in millions) Previously Reported Effects of Adoption As Adjusted Total current assets $ 11,673 $ 284 $ 11,957 Film and television costs $ 7,071 $ 11 $ 7,082 Other noncurrent assets, net $ 1,872 $ (68 ) $ 1,804 Total assets $ 71,073 $ 227 $ 71,300 Total current liabilities $ 9,602 $ 330 $ 9,932 Other noncurrent liabilities $ 4,109 $ 44 $ 4,153 Total equity $ 43,188 $ (147 ) $ 43,041 Total liabilities and equity $ 71,073 $ 227 $ 71,300

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments [Line Items]
Investment Summary	December 31 (in millions) 2018 2017 Equity method $ 4,035 $ 3,546 Marketable equity securities 341 433 Nonmarketable equity securities 1,805 1,186 Other investments 1,796 1,785 Total investments 7,977 6,950 Less: Current investments 94 19 Noncurrent investments $ 7,883 $ 6,931
Investment and other income (loss), net	Investment and Other Income (Loss), Net Year ended December 31 (in millions) 2018 2017 2016 Equity in net income (losses) of investees, net $ (364 ) $ 107 $ (104 ) Realized and unrealized gains (losses) on equity securities, net (187 ) (17 ) 12 Other income (loss), net 326 331 529 Investment and other income (loss), net $ (225 ) $ 421 $ 437
NBCUniversal Media LLC [Member]
Investments [Line Items]
Investment Summary	December 31 (in millions) 2018 2017 Equity method $ 707 $ 690 Marketable equity securities 162 430 Nonmarketable equity securities 811 696 Total investments $ 1,680 $ 1,816
Investment and other income (loss), net	Investment and Other Income (Loss), Net Year ended December 31 (in millions) 2018 2017 2016 Equity in net income (losses) of investees, net $ (371 ) $ (201 ) $ (99 ) Realized and unrealized gains (losses) on equity securities, net (217 ) — 3 Other income (loss), net 67 57 120 Investment and other income (loss), net $ (521 ) $ (144 ) $ 24

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and Equipment	December 31 (in millions) Weighted-Average 2018 2017 Cable distribution system 11 years $ 38,380 $ 36,046 Customer premise equipment 6 years 26,208 26,392 Other equipment 8 years 12,437 10,518 Buildings and leasehold improvements 30 years 14,188 12,346 Construction in process N/A 2,991 1,752 Land N/A 1,539 1,332 Property and equipment, at cost 95,743 88,386 Less: Accumulated depreciation 51,306 49,916 Property and equipment, net $ 44,437 $ 38,470
NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	December 31 (in millions) Weighted-Average 2018 2017 Buildings and leasehold improvements 31 years $ 8,877 $ 8,124 Furniture, fixtures and equipment 11 years 5,501 4,843 Construction in process N/A 2,676 1,506 Land N/A 1,129 1,039 Property and equipment, at cost 18,183 15,512 Less: Accumulated depreciation 4,994 4,166 Property and equipment, net $ 13,189 $ 11,346

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets [Line Items]
Schedule of Goodwill	Note 12: Goodwill and Intangible Assets Goodwill NBCUniversal (in millions) Cable Cable Broadcast Filmed Theme Sky Corporate Total Balance, December 31, 2016 $ 12,645 $ 13,183 $ 806 $ 2,993 $ 6,341 $ — $ 12 $ 35,980 Acquisitions 140 241 — 32 — — 5 418 Dispositions — — — — — — (11 ) (11 ) Adjustments (a) (1 ) 1 — 185 — — 1 186 Foreign currency translation — 2 — 2 203 — — 207 Balance, December 31, 2017 12,784 13,427 806 3,212 6,544 — 7 36,780 Acquisitions (b) — — 36 — — 29,889 — 29,925 Dispositions — — — (8 ) — — (5 ) (13 ) Adjustments — (13 ) 1 (9 ) — — — (21 ) Foreign currency translation — (7 ) — (11 ) 140 (639 ) — (517 ) Balance, December 31, 2018 $ 12,784 $ 13,407 $ 843 $ 3,184 $ 6,684 $ 29,250 $ 2 $ 66,154 (a) Adjustments in 2017 primarily included the updated allocation of the purchase price for DreamWorks Animation. (b) Acquisitions in 2018 primarily included the Sky acquisition. As of December 31, 2018, all goodwill resulting from the Sky acquisition has been presented in the Sky segment. Our evaluation of reporting units and assignment of goodwill resulting from the Sky acquisition are preliminary and subject to change. We will finalize the analysis no later than one year from the acquisition date. See Note 8 for further information on the Sky acquisition.
Other Intangible Assets	Intangible Assets 2018 (a) 2017 December 31 (in millions) Weighted-Average Original Useful Life as of December 31, 2018 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Indefinite-Lived Intangible Assets: Franchise rights N/A $ 59,365 $ 59,364 Trade names N/A 9,633 2,981 FCC licenses N/A 2,333 2,238 Finite-Lived Intangible Assets: Customer relationships 16 years 25,046 $ (6,682 ) 13,612 $ (5,819 ) Software 5 years 11,395 (5,990 ) 8,258 (4,846 ) Patents and other technology rights 7 years 260 (234 ) 259 (221 ) Other agreements and rights 18 years 3,885 (1,288 ) 2,736 (1,065 ) Total $ 111,917 $ (14,194 ) $ 89,448 $ (11,951 ) (a) In 2018, we recorded intangible assets in connection with the Sky acquisition, which primarily consisted of customer relationships and trade names (see Note 8 for additional information).
Amortization of Intangible Assets	Estimated Amortization Expense of Finite-Lived Intangible Assets (in millions) 2019 $ 3,719 2020 $ 3,490 2021 $ 3,104 2022 $ 2,689 2023 $ 2,260
NBCUniversal Media LLC [Member]
Goodwill And Intangible Assets [Line Items]
Schedule of Goodwill	Goodwill (in millions) Cable Broadcast Filmed Theme Total Balance, December 31, 2016 $ 13,183 $ 806 $ 2,993 $ 6,341 $ 23,323 Acquisitions 241 — 32 — 273 Adjustments (a) 1 — 185 — 186 Foreign currency translation 2 — 2 203 207 Balance, December 31, 2017 13,427 806 3,212 6,544 23,989 Acquisitions — 36 — — 36 Dispositions — — (8 ) — (8 ) Adjustments (13 ) 1 (9 ) — (21 ) Foreign currency translation (7 ) — (11 ) 140 122 Balance, December 31, 2018 $ 13,407 $ 843 $ 3,184 $ 6,684 $ 24,118 (a) Adjustments in 2017 primarily included the updated allocation of the purchase price for DreamWorks Animation.
Other Intangible Assets	Intangible Assets 2018 2017 December 31 (in millions) Weighted-Average Gross Accumulated Gross Accumulated Finite-Lived Intangible Assets: Customer relationships 19 years $ 13,269 $ (6,283 ) $ 13,301 $ (5,643 ) Software 5 years 1,779 (932 ) 1,516 (737 ) Other 19 years 3,619 (1,375 ) 2,580 (1,205 ) Indefinite-Lived Intangible Assets: Trade names N/A 2,981 2,981 FCC licenses N/A 608 513 Total $ 22,256 $ (8,590 ) $ 20,891 $ (7,585 )
Amortization of Intangible Assets	Estimated Amortization Expense of Finite-Lived Intangible Assets (in millions) 2019 $ 1,059 2020 $ 1,039 2021 $ 936 2022 $ 861 2023 $ 839

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Plans	Year ended December 31 (in millions) 2018 2017 2016 Benefit obligation $ 2,885 $ 2,539 $ 2,164 Interest expense $ 222 $ 209 $ 178
Postretirement and Pension Benefits	Year ended December 31 (in millions) 2018 2017 Benefit obligation $ 408 $ 425 Amounts in accumulated other comprehensive income not yet recognized in benefits expense $ (439 ) $ (458 )
NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Plans	Year ended December 31 (in millions) 2018 2017 2016 Benefit obligation $ 719 $ 621 $ 494 Interest expense $ 58 $ 64 $ 48
Postretirement and Pension Benefits	Year ended December 31 (in millions) 2018 2017 Benefit obligation $ 47 $ 51 Amounts in accumulated other comprehensive income not yet recognized in benefits expense $ (163 ) $ (177 )

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of common stock outstanding	Shares of Common Stock Outstanding (in millions) A B Balance, December 31, 2015 4,875 9 Stock compensation plans 23 — Repurchases and retirements of common stock (161 ) — Employee stock purchase plans 5 — Balance, December 31, 2016 4,742 9 Stock compensation plans 19 — Repurchases and retirements of common stock (131 ) — Employee stock purchase plans 5 — Balance, December 31, 2017 4,635 9 Stock compensation plans 15 — Repurchases and retirements of common stock (140 ) — Employee stock purchase plans 7 — Balance, December 31, 2018 4,517 9
Schedule of shares repurchased	Share Repurchases Under Share Repurchase Program Authorization Year ended December 31 (in millions) 2018 2017 2016 Cash consideration $ 5,000 $ 5,000 $ 5,000 Shares repurchased 140 131 161
Schedule of accumulated other comprehensive income (loss)	Accumulated Other Comprehensive Income (Loss) December 31 (in millions) 2018 2017 Unrealized gains (losses) on marketable securities $ 3 $ (43 ) Deferred gains (losses) on cash flow hedges 55 9 Unrecognized gains (losses) on employee benefit obligations 325 260 Cumulative translation adjustments (751 ) 153 Accumulated other comprehensive income (loss), net of deferred taxes $ (368 ) $ 379

Share-Based Compensation, Stock

Share-Based Compensation, Stock Options and Restricted Stock Units (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of recognized share-based compensation expense	The tables below provide information on our share-based compensation. Recognized Share-Based Compensation Expense Year ended December 31 (in millions) 2018 2017 2016 Restricted share units $ 402 $ 349 $ 306 Stock options 205 205 173 Employee stock purchase plans 32 32 28 Total $ 639 $ 586 $ 507
Schedule of stock option and restricted share units activity	Stock Options and Restricted Share Units As of December 31, 2018, unless otherwise stated (in millions, except per share data) Stock Options RSUs Awards granted during 2018 41 24 Weighted-average exercise price of awards granted during 2018 $ 35.81 Stock options outstanding and nonvested RSUs 200 51 Weighted-average exercise price of stock options outstanding $ 27.69 Weighted-average fair value at grant date of nonvested RSUs $ 33.77
Schedule of stock option and restricted share units fair value and significant assumptions	The table below presents the weighted-average fair value on the date of grant of RSUs and stock options awarded under our various plans and the related weighted-average valuation assumptions. Year ended December 31 2018 2017 2016 RSUs fair value $ 35.56 $ 37.77 $ 30.02 Stock options fair value $ 7.14 $ 7.01 $ 5.78 Stock Option Valuation Assumptions: Dividend yield 2.1 % 1.7 % 1.8 % Expected volatility 22.0 % 20.1 % 23.0 % Risk-free interest rate 2.7 % 2.2 % 1.5 % Expected option life (in years) 6.0 6.1 6.1

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Financial Information [Line Items]
Schedule of cash payments for interest and income taxes	Cash Payments for Interest and Income Taxes Year ended December 31 (in millions) 2018 2017 2016 Interest $ 2,897 $ 2,820 $ 2,565 Income taxes $ 2,355 $ 4,057 $ 3,693
Schedule of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheet to the total of the amounts reported in our consolidated statement of cash flows. December 31 (in millions) 2018 2017 Cash and cash equivalents $ 3,814 $ 3,428 Restricted cash included in other current assets 46 60 Restricted cash included in other noncurrent assets, net 49 83 Cash, cash equivalents and restricted cash, end of year $ 3,909 $ 3,571
Schedule of accumulated other comprehensive income (loss)	Accumulated Other Comprehensive Income (Loss) December 31 (in millions) 2018 2017 Unrealized gains (losses) on marketable securities $ 3 $ (43 ) Deferred gains (losses) on cash flow hedges 55 9 Unrecognized gains (losses) on employee benefit obligations 325 260 Cumulative translation adjustments (751 ) 153 Accumulated other comprehensive income (loss), net of deferred taxes $ (368 ) $ 379
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Schedule of cash payments for interest and income taxes	Cash Payments for Interest and Income Taxes Year ended December 31 (in millions) 2018 2017 2016 Interest $ 408 $ 517 $ 548 Income taxes $ 430 $ 282 $ 208
Schedule of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheet to the total of the amounts reported in our consolidated statement of cash flows. December 31 (in millions) 2018 2017 Cash and cash equivalents $ 1,444 $ 2,347 Restricted cash included in other noncurrent assets, net 20 30 Cash, cash equivalents and restricted cash, end of year $ 1,464 $ 2,377
Schedule of accumulated other comprehensive income (loss)	Accumulated Other Comprehensive Income (Loss) December 31 (in millions) 2018 2017 Unrealized gains (losses) on marketable securities $ — $ (233 ) Deferred gains (losses) on cash flow hedges 12 10 Unrecognized gains (losses) on employee benefit obligations 140 126 Cumulative translation adjustments 102 77 Accumulated other comprehensive income (loss) $ 254 $ (20 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitment And Contingencies [Line Items]
Schedule of minimum annual programming and talent commitments and operating leases	The table below summarizes our minimum annual programming and talent commitments and our minimum annual rental commitments under operating leases for office space, equipment and transponder service agreements. Programming and talent commitments include acquired film and television programming, including broadcast rights to sporting events, such as the Olympics, and other programming commitments, as well as various contracts with creative talent. As of December 31, 2018 (in millions) Programming and Talent Commitments Operating Leases 2019 $ 11,741 $ 759 2020 $ 10,468 $ 709 2021 $ 8,865 $ 616 2022 $ 5,193 $ 480 2023 $ 3,060 $ 414 Thereafter $ 17,142 $ 2,285
Schedule of rental expenses charged to operations	The table below presents our rental expense charged to operations. Year ended December 31 (in millions) 2018 2017 2016 Rental expense $ 779 $ 839 $ 744
NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Schedule of minimum annual programming and talent commitments and operating leases	The table below summarizes our minimum annual programming and talent commitments and our minimum annual rental commitments under operating leases for office space and equipment. Programming and talent commitments include acquired film and television programming, including broadcast rights to sporting events, such as the Olympics, and other programming commitments, as well as various contracts with creative talent. As of December 31, 2018 (in millions) Programming and Talent Commitments Operating Leases 2019 $ 5,371 $ 248 2020 $ 5,524 $ 232 2021 $ 3,922 $ 199 2022 $ 4,314 $ 168 2023 $ 2,181 $ 144 Thereafter $ 16,549 $ 1,380
Schedule of rental expenses charged to operations	The table below presents our rental expense charged to operations. Year ended December 31 (in millions) 2018 2017 2016 Rental expense $ 286 $ 274 $ 259

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	(in millions, except per share data) First Second Third Fourth Total 2018 Revenue $ 22,791 $ 21,735 $ 22,135 $ 27,846 $ 94,507 Operating income $ 4,645 $ 5,014 $ 4,836 $ 4,514 $ 19,009 Net income attributable to Comcast Corporation $ 3,118 $ 3,216 $ 2,886 $ 2,511 $ 11,731 Basic earnings per common share attributable to Comcast Corporation shareholders $ 0.67 $ 0.70 $ 0.63 $ 0.55 $ 2.56 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 0.66 $ 0.69 $ 0.62 $ 0.55 $ 2.53 Dividends declared per common share $ 0.19 $ 0.19 $ 0.19 $ 0.19 $ 0.76 2017 Revenue $ 20,587 $ 21,286 $ 21,081 $ 22,075 $ 85,029 Operating income $ 4,542 $ 4,568 $ 4,779 $ 4,129 $ 18,018 Net income attributable to Comcast Corporation (a) $ 2,573 $ 2,521 $ 2,642 $ 14,999 $ 22,735 Basic earnings per common share attributable to Comcast Corporation shareholders $ 0.54 $ 0.53 $ 0.56 $ 3.22 $ 4.83 Diluted earnings per common share attributable to Comcast Corporation shareholders $ 0.53 $ 0.52 $ 0.55 $ 3.17 $ 4.75 Dividends declared per common share $ 0.1575 $ 0.1575 $ 0.1575 $ 0.1575 $ 0.63 Minor differences may exist due to rounding. (a) In the fourth quarter of 2017, net income attributable to Comcast Corporation included a $12.7 billion net income tax benefit as a result of the impacts of the 2017 tax reform legislation. See Note 5 for additional information.

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Statement of Income	Condensed Consolidating Statement of Income For the Year Ended December 31, 2018 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 94,507 $ — $ 94,507 Management fee revenue 1,197 — 1,175 — — (2,372 ) — Total revenue 1,197 — 1,175 — 94,507 (2,372 ) 94,507 Costs and Expenses: Programming and production — — — — 29,692 — 29,692 Other operating and administrative 947 — 1,175 1,023 27,321 (2,372 ) 28,094 Advertising, marketing and promotion — — — — 7,036 — 7,036 Depreciation 46 — — — 8,235 — 8,281 Amortization 5 — — — 2,731 — 2,736 Other operating gains — — — — (341 ) — (341 ) Total costs and expenses 998 — 1,175 1,023 74,674 (2,372 ) 75,498 Operating income (loss) 199 — — (1,023 ) 19,833 — 19,009 Interest expense (2,644 ) (12 ) (190 ) (430 ) (266 ) — (3,542 ) Investment and other income (loss), net 13,638 13,604 12,021 6,694 5,054 (51,236 ) (225 ) Income (loss) before income taxes 11,193 13,592 11,831 5,241 24,621 (51,236 ) 15,242 Income tax (expense) benefit 538 8 40 (4 ) (3,962 ) — (3,380 ) Net income (loss) 11,731 13,600 11,871 5,237 20,659 (51,236 ) 11,862 Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 131 — 131 Net income (loss) attributable to Comcast Corporation $ 11,731 $ 13,600 $ 11,871 $ 5,237 $ 20,528 $ (51,236 ) $ 11,731 Comprehensive income (loss) attributable to Comcast Corporation $ 10,908 $ 13,623 $ 11,873 $ 5,279 $ 19,553 $ (50,328 ) $ 10,908 Condensed Consolidating Statement of Income For the Year Ended December 31, 2017 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 85,029 $ — $ 85,029 Management fee revenue 1,128 — 1,109 — — (2,237 ) — Total revenue 1,128 — 1,109 — 85,029 (2,237 ) 85,029 Costs and Expenses: Programming and production — — — — 25,355 — 25,355 Other operating and administrative 766 — 1,109 1,044 24,767 (2,237 ) 25,449 Advertising, marketing and promotion — — — — 6,519 — 6,519 Depreciation 31 — — — 7,883 — 7,914 Amortization 6 — — — 2,210 — 2,216 Other operating gains — — — — (442 ) — (442 ) Total costs and expenses 803 — 1,109 1,044 66,292 (2,237 ) 67,011 Operating income (loss) 325 — — (1,044 ) 18,737 — 18,018 Interest expense (2,172 ) (12 ) (207 ) (456 ) (239 ) — (3,086 ) Investment and other income (loss), net 24,076 21,767 19,610 6,584 5,545 (77,161 ) 421 Income (loss) before income taxes 22,229 21,755 19,403 5,084 24,043 (77,161 ) 15,353 Income tax (expense) benefit 506 156 71 (4 ) 6,840 — 7,569 Net income (loss) 22,735 21,911 19,474 5,080 30,883 (77,161 ) 22,922 Less: Net income loss attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 187 — 187 Net income (loss) attributable to Comcast Corporation $ 22,735 $ 21,911 $ 19,474 $ 5,080 $ 30,696 $ (77,161 ) $ 22,735 Comprehensive income (loss) attributable to Comcast Corporation $ 22,822 $ 21,909 $ 19,477 $ 5,054 $ 30,558 $ (76,998 ) $ 22,822 Condensed Consolidating Statement of Income For the Year Ended December 31, 2016 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Revenue: Service revenue $ — $ — $ — $ — $ 80,736 $ — $ 80,736 Management fee revenue 1,067 — 1,049 — — (2,116 ) — Total revenue 1,067 — 1,049 — 80,736 (2,116 ) 80,736 Costs and Expenses: Programming and production — — — — 24,348 — 24,348 Other operating and administrative 813 — 1,049 932 23,162 (2,116 ) 23,840 Advertising, marketing and promotion — — — — 6,291 — 6,291 Depreciation 28 — — — 7,436 — 7,464 Amortization 6 — — — 1,956 — 1,962 Other operating gains — — — — — — — Total costs and expenses 847 — 1,049 932 63,193 (2,116 ) 63,905 Operating income (loss) 220 — — (932 ) 17,543 — 16,831 Interest expense (1,941 ) (12 ) (239 ) (456 ) (294 ) — (2,942 ) Investment and other income (loss), net 9,799 9,289 8,703 5,572 4,515 (37,441 ) 437 Income (loss) before income taxes 8,078 9,277 8,464 4,184 21,764 (37,441 ) 14,326 Income tax (expense) benefit 600 6 84 (13 ) (5,975 ) — (5,298 ) Net income (loss) 8,678 9,283 8,548 4,171 15,789 (37,441 ) 9,028 Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock — — — — 350 — 350 Net income (loss) attributable to Comcast Corporation $ 8,678 $ 9,283 $ 8,548 $ 4,171 $ 15,439 $ (37,441 ) $ 8,678 Comprehensive income (loss) attributable to Comcast Corporation $ 8,950 $ 9,325 $ 8,554 $ 4,248 $ 15,529 $ (37,656 ) $ 8,950
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2018 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ (2,245 ) $ 126 $ (112 ) $ (1,430 ) $ 27,958 $ — $ 24,297 Investing Activities: Net transactions with affiliates (26,179 ) (575 ) 112 1,336 25,306 — — Capital expenditures (27 ) — — — (9,747 ) — (9,774 ) Cash paid for intangible assets (4 ) — — — (1,931 ) — (1,935 ) Acquisitions and construction of real estate properties (105 ) — — — (38 ) — (143 ) Construction of Universal Beijing Resort — — — — (460 ) — (460 ) Acquisitions, net of cash acquired — — — — (38,219 ) — (38,219 ) Proceeds from sales of businesses and investments — — — 68 73 — 141 Purchases of investments (126 ) — — (50 ) (1,081 ) — (1,257 ) Deposits — — — — — — — Other 148 449 — — 196 — 793 Net cash provided by (used in) investing activities (26,293 ) (126 ) 112 1,354 (25,901 ) — (50,854 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net (902 ) — — — 1,281 — 379 Proceeds from borrowings 44,113 — — — 668 — 44,781 Repurchases and repayments of debt (5,737 ) — — (4 ) (3,057 ) — (8,798 ) Repurchases of common stock under repurchase program and employee plans (5,320 ) — — — — — (5,320 ) Dividends paid (3,352 ) — — — — — (3,352 ) Purchase of Universal Studios Japan noncontrolling interests — — — — — — — Issuances of common stock — — — — — — — Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (277 ) — (277 ) Other (201 ) — — — (72 ) — (273 ) Net cash provided by (used in) financing activities 28,601 — — (4 ) (1,457 ) — 27,140 Impact of foreign currency on cash, cash equivalents and restricted cash (63 ) — — — (182 ) — (245 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — (80 ) 418 — 338 Cash, cash equivalents and restricted cash, beginning of year — — — 496 3,075 — 3,571 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 416 $ 3,493 $ — $ 3,909 Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2017 (in millions) Comcast Parent Comcast Holdings CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ 151 $ 15 $ (147 ) $ (1,439 ) $ 22,681 $ — $ 21,261 Investing Activities: Net transactions with affiliates 5,578 (5 ) 757 1,447 (7,777 ) — — Capital expenditures (12 ) — — — (9,538 ) — (9,550 ) Cash paid for intangible assets (4 ) — — — (1,601 ) — (1,605 ) Acquisitions and construction of real estate properties (267 ) — — — (151 ) — (418 ) Construction of Universal Beijing Resort — — — — (71 ) — (71 ) Acquisitions, net of cash acquired — — — — (532 ) — (532 ) Proceeds from sales of businesses and investments — — — 14 136 — 150 Purchases of investments (70 ) (10 ) (60 ) (62 ) (2,090 ) — (2,292 ) Deposits — — — — — — — Other 101 — — 58 626 — 785 Net cash provided by (used in) investing activities 5,326 (15 ) 697 1,457 (20,998 ) — (13,533 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net (837 ) — — — (1,068 ) — (1,905 ) Proceeds from borrowings 5,997 — — — 5,469 — 11,466 Repurchases and repayments of debt (2,288 ) — (550 ) (4 ) (3,522 ) — (6,364 ) Repurchases of common stock under repurchase program and employee plans (5,435 ) — — — — — (5,435 ) Dividends paid (2,883 ) — — — — — (2,883 ) Purchase of Universal Studios Japan noncontrolling interests — — — — (2,299 ) — (2,299 ) Issuances of common stock — — — — — — — Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (252 ) — (252 ) Other (31 ) — — — 131 — 100 Net cash provided by (used in) financing activities (5,477 ) — (550 ) (4 ) (1,541 ) — (7,572 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — 14 142 — 156 Cash, cash equivalents and restricted cash, beginning of year — — — 482 2,933 — 3,415 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 496 $ 3,075 $ — $ 3,571 Condensed Consolidating Statement of Cash Flows For the Year Ended December 31, 2016 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Net cash provided by (used in) operating activities $ 349 $ (336 ) $ (100 ) $ (1,453 ) $ 21,231 $ — $ 19,691 Investing Activities: Net transactions with affiliates (1,956 ) 336 100 2,642 (1,122 ) — — Capital expenditures (13 ) — — — (9,122 ) — (9,135 ) Cash paid for intangible assets (9 ) — — — (1,543 ) — (1,552 ) Acquisitions and construction of real estate properties (35 ) — — — (393 ) — (428 ) Construction of Universal Beijing Resort — — — — (22 ) — (22 ) Acquisitions, net of cash acquired — — — — (3,929 ) — (3,929 ) Proceeds from sales of businesses and investments — — — 104 114 — 218 Purchases of investments (40 ) — — (210 ) (1,447 ) — (1,697 ) Deposits — — — — (1,749 ) — (1,749 ) Other (108 ) — — (35 ) 172 — 29 Net cash provided by (used in) investing activities (2,161 ) 336 100 2,501 (19,041 ) — (18,265 ) Financing Activities: Proceeds from (repayments of) short-term borrowings, net 1,339 — — — 451 — 1,790 Proceeds from borrowings 9,231 — — — — — 9,231 Repurchases and repayments of debt (750 ) — — (1,005 ) (1,297 ) — (3,052 ) Repurchases of common stock under repurchase program and employee plans (5,352 ) — — — — — (5,352 ) Dividends paid (2,601 ) — — — — — (2,601 ) Issuances of common stock 23 — — — — — 23 Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock — — — — (253 ) — (253 ) Other (78 ) — — 25 (167 ) — (220 ) Net cash provided by (used in) financing activities 1,812 — — (980 ) (1,266 ) — (434 ) Increase (decrease) in cash and cash equivalents and restricted cash — — — 68 924 — 992 Cash, cash equivalents and restricted cash, beginning of year — — — 414 2,009 — 2,423 Cash, cash equivalents and restricted cash, end of year $ — $ — $ — $ 482 $ 2,933 $ — $ 3,415
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet December 31, 2018 (in millions) Comcast Parent Comcast Holdings CCCL Parent NBCUniversal Media Parent Non- Guarantor Subsidiaries Elimination and Consolidation Adjustments Consolidated Comcast Corporation Assets Cash and cash equivalents $ — $ — $ — $ 416 $ 3,398 $ — $ 3,814 Receivables, net — — — — 11,104 — 11,104 Programming rights — — — — 3,746 — 3,746 Other current assets 66 20 — 28 3,070 — 3,184 Total current assets 66 20 — 444 21,318 — 21,848 Film and television costs — — — — 7,837 — 7,837 Investments 270 11 143 790 6,669 — 7,883 Investments in and amounts due from subsidiaries eliminated upon consolidation 157,264 147,028 130,214 53,853 97,872 (586,231 ) — Property and equipment, net 670 — — — 43,767 — 44,437 Franchise rights — — — — 59,365 — 59,365 Goodwill — — — — 66,154 — 66,154 Other intangible assets, net 11 — — — 38,347 — 38,358 Other noncurrent assets, net 1,057 208 — 85 4,910 (458 ) 5,802 Total assets $ 159,338 $ 147,267 $ 130,357 $ 55,172 $ 346,239 $ (586,689 ) $ 251,684 Liabilities and Equity Accounts payable and accrued expenses related to trade creditors $ 2 $ — $ — $ — $ 8,492 $ — $ 8,494 Accrued participations and residuals — — — — 1,808 — 1,808 Deferred revenue — — — — 2,182 — 2,182 Accrued expenses and other current liabilities 2,357 150 360 282 7,572 — 10,721 Current portion of long-term debt 699 — — 4 3,695 — 4,398 Total current liabilities 3,058 150 360 286 23,749 — 27,603 Long-term debt, less current portion 81,661 146 2,100 7,748 15,690 — 107,345 Deferred income taxes — 314 — 65 27,734 (524 ) 27,589 Other noncurrent liabilities 3,006 — — 1,201 11,056 66 15,329 Redeemable noncontrolling interests and redeemable subsidiary preferred stock — — — — 1,316 — 1,316 Equity: Common stock 54 — — — — — 54 Other shareholders’ equity 71,559 146,657 127,897 45,872 265,805 (586,231 ) 71,559 Total Comcast Corporation shareholders’ equity 71,613 146,657 127,897 45,872 265,805 (586,231 ) 71,613 Noncontrolling interests — — — — 889 — 889 Total equity 71,613 146,657 127,897 45,872 266,694 (586,231 ) 72,502 Total liabilities and equity $ 159,338 $ 147,267 $ 130,357 $ 55,172 $ 346,239 $ (586,689 ) $ 251,684 Condensed Consolidating Balance Sheet December 31, 2017 (in millions) Comcast Parent Comcast CCCL Parent NBCUniversal Media Parent Non- Elimination Consolidated Assets Cash and cash equivalents $ — $ — $ — $ 496 $ 2,932 $ — $ 3,428 Receivables, net — — — — 8,834 — 8,834 Programming rights — — — — 1,613 — 1,613 Other current assets 60 — 7 25 2,376 — 2,468 Total current assets 60 — 7 521 15,755 — 16,343 Film and television costs — — — — 7,087 — 7,087 Investments 146 21 108 693 5,963 — 6,931 Investments in and amounts due from subsidiaries eliminated upon consolidation 117,164 142,519 139,528 50,102 113,332 (562,645 ) — Property and equipment, net 551 — — — 37,919 — 38,470 Franchise rights — — — — 59,364 — 59,364 Goodwill — — — — 36,780 — 36,780 Other intangible assets, net 12 — — — 18,121 — 18,133 Other noncurrent assets, net 435 708 — 88 3,437 (314 ) 4,354 Total assets $ 118,368 $ 143,248 $ 139,643 $ 51,404 $ 297,758 $ (562,959 ) $ 187,462 Liabilities and Equity Accounts payable and accrued expenses related to trade creditors $ 16 $ — $ — $ — $ 6,892 $ — $ 6,908 Accrued participations and residuals — — — — 1,644 — 1,644 Deferred revenue — — — — 1,687 — 1,687 Accrued expenses and other current liabilities 1,888 92 333 326 3,981 — 6,620 Current portion of long-term debt 2,810 — — 4 2,320 — 5,134 Total current liabilities 4,714 92 333 330 16,524 — 21,993 Long-term debt, less current portion 42,428 140 2,100 7,751 7,003 — 59,422 Deferred income taxes — 285 — 67 24,250 (343 ) 24,259 Other noncurrent liabilities 2,610 — — 1,128 7,205 29 10,972 Redeemable noncontrolling interests and redeemable subsidiary preferred stock — — — — 1,357 — 1,357 Equity: Common stock 55 — — — — — 55 Other shareholders’ equity 68,561 142,731 137,210 42,128 240,576 (562,645 ) 68,561 Total Comcast Corporation shareholders’ equity 68,616 142,731 137,210 42,128 240,576 (562,645 ) 68,616 Noncontrolling interests — — — — 843 — 843 Total equity 68,616 142,731 137,210 42,128 241,419 (562,645 ) 69,459 Total liabilities and equity $ 118,368 $ 143,248 $ 139,643 $ 51,404 $ 297,758 $ (562,959 ) $ 187,462

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Related Party Transactions Condensed Financial Statements	The following tables present transactions with Comcast and its consolidated subsidiaries that are included in our consolidated financial statements. Consolidated Statement of Income Year ended December 31 (in millions) 2018 2017 2016 Transactions with Comcast and Consolidated Subsidiaries Revenue $ 2,156 $ 1,837 $ 1,742 Total costs and expenses $ (245 ) $ (214 ) $ (220 ) Interest expense and investment and other income (loss), net $ (54 ) $ (250 ) $ (69 ) Consolidated Balance Sheet December 31 (in millions) 2018 2017 Transactions with Comcast and Consolidated Subsidiaries Receivables, net $ 464 $ 326 Note receivable from Comcast $ 2,054 — Accounts payable and accrued expenses related to trade creditors $ 78 $ 54 Accrued expenses and other current liabilities $ 32 $ 50 Note payable to Comcast $ 54 $ 1,831 Long-term debt $ 701 $ 610 Other noncurrent liabilities $ 410 $ 389

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions, £ in Billions	Oct. 09, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018segmentbusiness
Business And Basis Of Presentation [Line Items]
Number of primary businesses | business				3
NBCUniversal Media LLC [Member]
Business And Basis Of Presentation [Line Items]
Number of reportable segments				4
Cable Communications [Member]
Business And Basis Of Presentation [Line Items]
Number of reportable segments				1
NBCUniversal Segments [Member]
Business And Basis Of Presentation [Line Items]
Number of reportable segments				4
Sky Limited [Member]
Business And Basis Of Presentation [Line Items]
Number of reportable segments				1
Sky Limited [Member]
Business And Basis Of Presentation [Line Items]
Interest in business acquired in acquisition		100.00%	100.00%
Cash consideration transferred by Comcast	$ 39,387	$ 39,400	£ 30.2

Segment Information (Narrative)

Segment Information (Narrative) (Details) customer in Millions	Dec. 31, 2018customer
Cable Communications [Member]
Segment Reporting Information [Line Items]
Total customer relationships	30.3
Cable Communications [Member] | High-speed Internet Customers [Member]
Segment Reporting Information [Line Items]
Number of customers	27.2
Cable Communications [Member] | Video Customers [Member]
Segment Reporting Information [Line Items]
Number of customers	22
Cable Communications [Member] | Voice Customers [Member]
Segment Reporting Information [Line Items]
Number of customers	11.4
Cable Communications [Member] | Security And Automation Customers [Member]
Segment Reporting Information [Line Items]
Number of customers	1.3
Cable Communications [Member] | Residential [Member]
Segment Reporting Information [Line Items]
Total customer relationships	28
Cable Communications [Member] | Business Customers [Member]
Segment Reporting Information [Line Items]
Total customer relationships	2.3
Sky Limited [Member]
Segment Reporting Information [Line Items]
Retail customer relationships	23.6

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financial Data by Business Segment
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Adjusted EBITDA									30,165	27,956	26,257
Depreciation and Amortization									11,017	10,130	9,426
Capital Expenditures									9,774	9,550	9,135
Cash Paid for Intangible Assets									1,935	1,605	1,552
NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									35,895	32,950	31,398
Adjusted EBITDA									8,633	8,181	7,163
Depreciation and Amortization									2,108	2,041	1,805
Capital Expenditures									1,730	1,502	1,452
Cash Paid for Intangible Assets									448	295	283
Cable Communications [Member]
Financial Data by Business Segment
Revenue									55,143	53,070	50,577
Depreciation and Amortization										8,006	7,538
Cable Networks [Member]
Financial Data by Business Segment
Revenue									11,773	10,497	10,324
Cable Networks [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									11,773	10,497	10,324
Broadcast Television [Member]
Financial Data by Business Segment
Revenue									11,439	9,563	10,085
Broadcast Television [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									11,439	9,563	10,085
Filmed Entertainment [Member]
Financial Data by Business Segment
Revenue									7,152	7,595	6,229
Filmed Entertainment [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									7,152	7,595	6,229
Theme Parks [Member]
Financial Data by Business Segment
Revenue									5,683	5,443	4,946
Theme Parks [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									5,683	5,443	4,946
NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue									35,761	32,836	31,276
Adjusted EBITDA									8,598	8,218	7,138
Depreciation and Amortization									2,108	2,041	1,805
Capital Expenditures									1,730	1,502	1,452
Cash Paid for Intangible Assets									448	295	283
Sky Limited [Member]
Financial Data by Business Segment
Revenue									4,587	0	0
Operating Segments [Member] | Cable Communications [Member]
Financial Data by Business Segment
Revenue									55,143	53,070	50,577
Adjusted EBITDA									22,447	21,068	20,014
Depreciation and Amortization									8,264	8,006	7,538
Capital Expenditures									7,716	7,952	7,596
Cash Paid for Intangible Assets									1,282	1,241	1,243
Operating Segments [Member] | Cable Networks [Member]
Financial Data by Business Segment
Revenue									11,773	10,497	10,324
Adjusted EBITDA									4,428	4,053	3,681
Depreciation and Amortization									738	755	745
Capital Expenditures									42	33	32
Cash Paid for Intangible Assets									23	19	20
Operating Segments [Member] | Cable Networks [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									11,773	10,497	10,324
Adjusted EBITDA									4,428	4,053	3,681
Depreciation and Amortization									738	755	745
Capital Expenditures									42	33	32
Cash Paid for Intangible Assets									23	19	20
Operating Segments [Member] | Broadcast Television [Member]
Financial Data by Business Segment
Revenue									11,439	9,563	10,085
Adjusted EBITDA									1,657	1,251	1,293
Depreciation and Amortization									146	133	125
Capital Expenditures									204	180	153
Cash Paid for Intangible Assets									81	22	19
Operating Segments [Member] | Broadcast Television [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									11,439	9,563	10,085
Adjusted EBITDA									1,657	1,251	1,293
Depreciation and Amortization									146	133	125
Capital Expenditures									204	180	153
Cash Paid for Intangible Assets									81	22	19
Operating Segments [Member] | Filmed Entertainment [Member]
Financial Data by Business Segment
Revenue									7,152	7,595	6,229
Adjusted EBITDA									734	1,276	662
Depreciation and Amortization									145	109	47
Capital Expenditures									35	58	33
Cash Paid for Intangible Assets									25	23	16
Operating Segments [Member] | Filmed Entertainment [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									7,152	7,595	6,229
Adjusted EBITDA									734	1,276	662
Depreciation and Amortization									145	109	47
Capital Expenditures									35	58	33
Cash Paid for Intangible Assets									25	23	16
Operating Segments [Member] | Theme Parks [Member]
Financial Data by Business Segment
Revenue									5,683	5,443	4,946
Adjusted EBITDA									2,455	2,384	2,190
Depreciation and Amortization									660	648	512
Capital Expenditures									1,143	960	922
Cash Paid for Intangible Assets									173	78	72
Operating Segments [Member] | Theme Parks [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									5,683	5,443	4,946
Adjusted EBITDA									2,455	2,384	2,190
Depreciation and Amortization									660	648	512
Capital Expenditures									1,143	960	922
Cash Paid for Intangible Assets									173	78	72
Operating Segments [Member] | Sky Limited [Member]
Financial Data by Business Segment
Revenue									4,587
Adjusted EBITDA									692
Depreciation and Amortization									539
Capital Expenditures									222
Cash Paid for Intangible Assets									137
Corporate, Non-Segment [Member]
Financial Data by Business Segment
Revenue									1,403	1,193	886
Adjusted EBITDA									(1,545)	(1,372)	(849)
Depreciation and Amortization									106	83	83
Capital Expenditures									106	96	87
Cash Paid for Intangible Assets									68	69	26
Corporate, Non-Segment [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									212	179	157
Adjusted EBITDA									(645)	(779)	(674)
Depreciation and Amortization									419	396	376
Capital Expenditures									306	271	312
Cash Paid for Intangible Assets									146	153	156
Corporate, Non-Segment [Member] | NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue									63	45	20
Adjusted EBITDA									(680)	(741)	(699)
Depreciation and Amortization									419	396	376
Capital Expenditures									306	271	312
Cash Paid for Intangible Assets									146	153	156
Eliminations [Member]
Financial Data by Business Segment
Revenue									(2,387)	(2,070)	(2,003)
Adjusted EBITDA									(27)	42	(46)
Depreciation and Amortization									0	0	0
Capital Expenditures									0	0	0
Cash Paid for Intangible Assets									0	0	0
Eliminations [Member] | NBCUniversal Media LLC [Member]
Financial Data by Business Segment
Revenue									(364)	(327)	(343)
Adjusted EBITDA									4	(4)	11
Depreciation and Amortization									0	0	0
Capital Expenditures									0	0	0
Cash Paid for Intangible Assets									0	0	0
Eliminations [Member] | NBCUniversal Segments [Member]
Financial Data by Business Segment
Revenue									(349)	(307)	(328)
Adjusted EBITDA									4	(5)	11
Depreciation and Amortization									0	0	0
Capital Expenditures									0	0	0
Cash Paid for Intangible Assets									$ 0	$ 0	$ 0

Segment Information (Reconcilia

Segment Information (Reconciliation of Adjusted EBITDA from Segment to Consolidated Statements) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted EBITDA	$ 30,165	$ 27,956	$ 26,257
Adjustment for legal settlement	(125)	(250)	0
Adjustment for Sky transaction-related costs	(355)	0	0
Depreciation	(8,281)	(7,914)	(7,464)
Amortization	(2,736)	(2,216)	(1,962)
Other operating gains	341	442	0
Interest expense	(3,542)	(3,086)	(2,942)
Investment and other income (loss), net	(225)	421	437
Income before income taxes	15,242	15,353	14,326
NBCUniversal Media LLC [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted EBITDA	8,633	8,181	7,163
Depreciation	(1,001)	(994)	(861)
Amortization	(1,107)	(1,047)	(944)
Other operating gains	141	337	0
Interest expense	(489)	(727)	(595)
Investment and other income (loss), net	(521)	(144)	24
Income before income taxes	$ 5,656	$ 5,606	$ 4,787

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Cable Communications [Member]
Disaggregation of Revenue [Line Items]
Revenue									55,143	53,070	50,577
Cable Communications [Member] | Residential, High-Speed Internet [Member]
Disaggregation of Revenue [Line Items]
Revenue									17,144	15,681	14,421
Cable Communications [Member] | Residential, Video [Member]
Disaggregation of Revenue [Line Items]
Revenue									22,455	22,874	22,204
Cable Communications [Member] | Residential, Voice [Member]
Disaggregation of Revenue [Line Items]
Revenue									3,960	4,090	4,159
Cable Communications [Member] | Business Services [Member]
Disaggregation of Revenue [Line Items]
Revenue									7,129	6,437	5,705
Cable Communications [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,795	2,450	2,626
Cable Communications [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									$ 1,660	$ 1,538	$ 1,462
Cable Communications [Member] | Franchise And Other Regulatory Fees [Member]
Disaggregation of Revenue [Line Items]
Cable segment revenue types as percentage of total cable revenue									2.70%	2.80%	2.90%
Cable Networks [Member]
Disaggregation of Revenue [Line Items]
Revenue									$ 11,773	$ 10,497	$ 10,324
Cable Networks [Member] | Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue									6,826	6,081	5,978
Cable Networks [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									3,587	3,359	3,530
Cable Networks [Member] | Content Licensing And Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,360	1,057	816
Broadcast Television [Member]
Disaggregation of Revenue [Line Items]
Revenue									11,439	9,563	10,085
Broadcast Television [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									7,010	5,654	6,834
Broadcast Television [Member] | Content Licensing [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,182	2,114	1,837
Broadcast Television [Member] | Distribution And Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,247	1,795	1,414
Filmed Entertainment [Member]
Disaggregation of Revenue [Line Items]
Revenue									7,152	7,595	6,229
Filmed Entertainment [Member] | Content Licensing [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,899	2,956	2,518
Filmed Entertainment [Member] | Theatrical [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,111	2,192	1,560
Filmed Entertainment [Member] | Home Entertainment [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,048	1,287	1,182
Filmed Entertainment [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,094	1,160	969
Theme Parks [Member]
Disaggregation of Revenue [Line Items]
Revenue									5,683	5,443	4,946
NBCUniversal Segments [Member]
Disaggregation of Revenue [Line Items]
Revenue									35,761	32,836	31,276
Sky Limited [Member]
Disaggregation of Revenue [Line Items]
Revenue									4,587	0	0
Sky Limited [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									651	0	0
Sky Limited [Member] | Direct To Consumer [Member]
Disaggregation of Revenue [Line Items]
Revenue									3,632	0	0
Sky Limited [Member] | Content [Member]
Disaggregation of Revenue [Line Items]
Revenue									304	0	0
Corporate, Non-Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,403	1,193	886
Corporate, Non-Segment [Member] | NBCUniversal Segments [Member]
Disaggregation of Revenue [Line Items]
Revenue									63	45	20
Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue									(2,387)	(2,070)	(2,003)
Eliminations [Member] | NBCUniversal Segments [Member]
Disaggregation of Revenue [Line Items]
Revenue									(349)	(307)	(328)
NBCUniversal Media LLC [Member]
Disaggregation of Revenue [Line Items]
Revenue									35,895	32,950	31,398
NBCUniversal Media LLC [Member] | Cable Networks [Member]
Disaggregation of Revenue [Line Items]
Revenue									11,773	10,497	10,324
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue									6,826	6,081	5,978
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									3,587	3,359	3,530
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Content Licensing And Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,360	1,057	816
NBCUniversal Media LLC [Member] | Broadcast Television [Member]
Disaggregation of Revenue [Line Items]
Revenue									11,439	9,563	10,085
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenue									7,010	5,654	6,834
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Content Licensing [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,182	2,114	1,837
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Distribution And Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,247	1,795	1,414
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member]
Disaggregation of Revenue [Line Items]
Revenue									7,152	7,595	6,229
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Content Licensing [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,899	2,956	2,518
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Theatrical [Member]
Disaggregation of Revenue [Line Items]
Revenue									2,111	2,192	1,560
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Home Entertainment [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,048	1,287	1,182
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue									1,094	1,160	969
NBCUniversal Media LLC [Member] | Theme Parks [Member]
Disaggregation of Revenue [Line Items]
Revenue									5,683	5,443	4,946
NBCUniversal Media LLC [Member] | Corporate, Non-Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue									212	179	157
NBCUniversal Media LLC [Member] | Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue									$ (364)	$ (327)	$ (343)

Revenue (Revenue by Geographic

Revenue (Revenue by Geographic Location) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue									82,233	77,246	74,212
Foreign [Member]
Disaggregation of Revenue [Line Items]
Revenue									12,274	7,783	6,524
NBCUniversal Media LLC [Member]
Disaggregation of Revenue [Line Items]
Revenue									35,895	32,950	31,398
NBCUniversal Media LLC [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue									28,309	25,303	24,907
NBCUniversal Media LLC [Member] | Foreign [Member]
Disaggregation of Revenue [Line Items]
Revenue									$ 7,586	$ 7,647	$ 6,491

Revenue (Narrative) (Details)

Revenue (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018
Cable Communications [Member] | Residential [Member]
Revenue [Line Items]
Term of contract	2 years
Cable Communications [Member] | Business Services [Member]
Revenue [Line Items]
Annual revenue that estimates remaining performance obligations	6 months
Timing period of recognition	2 years
Cable Communications [Member] | Business Services [Member] | Minimum [Member]
Revenue [Line Items]
Term of contract	2 years
Cable Communications [Member] | Business Services [Member] | Maximum [Member]
Revenue [Line Items]
Term of contract	5 years
Cable Communications [Member] | Advertising [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	30 days
Cable Communications [Member] | Advertising [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	60 days
Cable Networks [Member] | Distribution [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	30 days
Cable Networks [Member] | Distribution [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	60 days
Cable Networks [Member] | Advertising [Member]
Revenue [Line Items]
Expected payment terms	30 days
Broadcast Television [Member] | Distribution [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	30 days
Broadcast Television [Member] | Distribution [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	60 days
Broadcast Television [Member] | Advertising [Member]
Revenue [Line Items]
Expected payment terms	30 days
Filmed Entertainment [Member] | Theatrical [Member]
Revenue [Line Items]
Expected payment terms	30 days
Filmed Entertainment [Member] | Content [Member]
Revenue [Line Items]
Timing period of recognition	2 years
Filmed Entertainment [Member] | Content [Member] | Minimum [Member]
Revenue [Line Items]
Annual revenue that estimates remaining performance obligations	1 year
Filmed Entertainment [Member] | Content [Member] | Maximum [Member]
Revenue [Line Items]
Annual revenue that estimates remaining performance obligations	2 years
Filmed Entertainment [Member] | Home Entertainment [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	60 days
Filmed Entertainment [Member] | Home Entertainment [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	90 days
Sky Limited [Member] | Direct To Consumer [Member]
Revenue [Line Items]
Timing period of recognition	2 years
Sky Limited [Member] | Direct To Consumer [Member] | Maximum [Member]
Revenue [Line Items]
Term of contract	2 years
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Distribution [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	30 days
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Distribution [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	60 days
NBCUniversal Media LLC [Member] | Cable Networks [Member] | Advertising [Member]
Revenue [Line Items]
Expected payment terms	30 days
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Distribution [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	30 days
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Distribution [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	60 days
NBCUniversal Media LLC [Member] | Broadcast Television [Member] | Advertising [Member]
Revenue [Line Items]
Expected payment terms	30 days
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Theatrical [Member]
Revenue [Line Items]
Expected payment terms	30 days
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Content [Member]
Revenue [Line Items]
Timing period of recognition	2 years
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Content [Member] | Minimum [Member]
Revenue [Line Items]
Annual revenue that estimates remaining performance obligations	1 year
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Content [Member] | Maximum [Member]
Revenue [Line Items]
Annual revenue that estimates remaining performance obligations	2 years
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Home Entertainment [Member] | Minimum [Member]
Revenue [Line Items]
Expected payment terms	60 days
NBCUniversal Media LLC [Member] | Filmed Entertainment [Member] | Home Entertainment [Member] | Maximum [Member]
Revenue [Line Items]
Expected payment terms	90 days

Revenue (Condensed Consolidated

Revenue (Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Condensed Consolidated Balance Sheet [Line Items]
Receivables, gross	$ 11,456	$ 9,122
Less: Allowance for doubtful accounts	352	288
Receivables, net	11,104	8,834
NBCUniversal Media LLC [Member]
Condensed Consolidated Balance Sheet [Line Items]
Receivables, gross	7,392	7,055
Less: Allowance for doubtful accounts	99	88
Receivables, net	7,293	6,967
Accounting Standards Update 2014-09 [Member]
Condensed Consolidated Balance Sheet [Line Items]
Noncurrent receivables (included in other noncurrent assets, net)	1,399	1,184
Contract acquisition and fulfillment costs (included in other noncurrent assets, net)	991	922
Noncurrent deferred revenue (included in other noncurrent liabilities)	650	497
Accounting Standards Update 2014-09 [Member] | NBCUniversal Media LLC [Member]
Condensed Consolidated Balance Sheet [Line Items]
Noncurrent receivables (included in other noncurrent assets, net)	1,180	1,093
Noncurrent deferred revenue (included in other noncurrent liabilities)	$ 481	$ 392

Programming and Production Co_3

Programming and Production Costs (Schedule) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Film Costs:
Released, less amortization	$ 1,600	$ 1,734
Completed, not released	144	50
In production and in development	1,063	1,149
Total film costs	2,807	2,933
Television Costs:
Released, less amortization	2,289	2,260
In production and in development	953	818
Total television costs	3,242	3,078
Programming rights, less amortization	5,534	2,689
Total film costs, television costs and programming rights	11,583	8,700
Less: Current portion of programming rights	3,746	1,613
Film and television costs	7,837	7,087
NBCUniversal Media LLC [Member]
Film Costs:
Released, less amortization	1,600	1,734
Completed, not released	144	50
In production and in development	1,063	1,149
Total film costs	2,807	2,933
Television Costs:
Released, less amortization	2,161	2,260
In production and in development	953	818
Total television costs	3,114	3,078
Programming rights, less amortization	2,694	2,677
Total film costs, television costs and programming rights	8,615	8,688
Less: Current portion of programming rights	1,323	1,606
Film and television costs	$ 7,292	$ 7,082

Programming and Production Co_4

Programming and Production Costs (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Film And Television Cost [Line Items]
Amortization of completed film and television production expected to be amortized during the next fiscal year	$ 1,600
Expected amortization percentage of released and unamortized film and television costs during the next three fiscal years	83.00%
Remaining unamortized costs of acquired film and television libraries	$ 396
Expected amortization percentage of unamortized acquired film and television library costs during the next three fiscal years	48.00%
NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Amortization of completed film and television production expected to be amortized during the next fiscal year	$ 1,600
Expected amortization percentage of released and unamortized film and television costs during the next three fiscal years	83.00%
Remaining unamortized costs of acquired film and television libraries	$ 396
Expected amortization percentage of unamortized acquired film and television library costs during the next three fiscal years	48.00%
Maximum [Member]
Film And Television Cost [Line Items]
Amortization period of acquired film and television library costs	20 years
Maximum [Member] | NBCUniversal Media LLC [Member]
Film And Television Cost [Line Items]
Amortization period of acquired film and television library costs	20 years

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Expense (Benefit):
Federal	$ 2,026	$ 2,411	$ 3,190
State	639	277	480
Foreign	425	389	194
Current income tax expense (benefit)	3,090	3,077	3,864
Deferred Expense (Benefit):
Federal	546	(10,651)	1,183
State	(167)	11	153
Foreign	(89)	(6)	98
Deferred income tax expense (benefit)	290	(10,646)	1,434
Income tax expense (benefit)	3,380	(7,569)	5,298
NBCUniversal Media LLC [Member]
Current Expense (Benefit):
Foreign	230	201	38
Deferred Expense (Benefit):
Foreign	(31)	(7)	96
Deferred income tax expense (benefit)	(39)	2	89
Withholding tax expense	163	187	158
U.S. domestic tax expense	(11)	11	13
Income tax expense (benefit)	$ 351	$ 392	$ 305

Income Taxes (Federal Statutory

Income Taxes (Federal Statutory) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Federal tax at statutory rate		$ 3,201	$ 5,374	$ 5,014
State income taxes, net of federal benefit		212	299	373
Foreign income taxed at different rates		147	70	65
Nontaxable income attributable to noncontrolling interests		(20)	(45)	(128)
Other adjustments		(138)	(229)	(67)
Excess tax benefits recognized on share-based compensation		(75)	(297)	0
Federal tax legislation	$ (12,700)	(120)	(12,682)	0
Income tax expense (benefit)		3,380	(7,569)	5,298
Adjustments to uncertain and effectively settled tax positions, net [Member]
Income Taxes [Line Items]
Other adjustments		144	(62)	24
Accrued interest on uncertain and effectively settled tax positions, net [Member]
Income Taxes [Line Items]
Other adjustments		$ 29	$ 3	$ 17

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Foreign income before taxes			$ 855	$ 1,000	$ 871
Change in net deferred tax liability related to acquisitions			(1,900)
Increase (decrease) in deferred income taxes			$ (167)	$ 11	153
Federal corporate income tax rate			21.00%	35.00%
Reduction of net deferred tax liabilities				$ 12,400
Net tax benefit related to cumulative undistributed foreign earnings and foreign tax credits				382
One-time repatriation tax on cumulative undistributed foreign earnings and profits				101
Income tax benefit, 2018 tax reform legislation		$ 128
Deferred tax liability attributable to temporary differences in other comprehensive income			$ 72
Deferred tax related to purchase of noncontrolling interest			42
Net deferred tax liability, franchise rights	$ 15,000		15,000
Deferred Tax Assets, Operating Loss Carryforwards	1,926		1,926	481
Liability for Uncertainty in Income Taxes, Noncurrent	1,012		1,012	809	$ 1,103
Unrecognized tax benefits that would impact effective tax rate	1,100		1,100
Unrecognized tax benefits, interest on income taxes accrued	203		203	173
Uncertain Tax Positions Indemnified by GE [Member]
Income Taxes [Line Items]
Liability for Uncertainty in Income Taxes, Noncurrent	153		153
Unrecognized tax benefits, interest on income taxes accrued	56		56	$ 43
Sky Limited [Member]
Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	1,500		1,500
Federal Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards	268		268
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards	6,600		6,600
Sky Limited [Member]
Income Taxes [Line Items]
Change in net deferred tax liability related to acquisitions			$ (1,900)
Increase (decrease) in deferred income taxes	$ 244

Income Taxes (Components of Net

Income Taxes (Components of Net Deferred Tax Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets:
Net operating loss carryforwards	$ 1,926	$ 481
Nondeductible accruals and other	2,656	2,092
Less: Valuation allowance	632	377
Total deferred tax assets, net of valuation allowance	3,950	2,196
Deferred Tax Liabilities:
Differences between book and tax basis of property and equipment and intangible assets	29,139	25,223
Differences between book and tax basis of investments	491	466
Differences between book and tax basis of long-term debt	604	673
Differences between book and tax basis of foreign subsidiaries and undistributed foreign earnings	85	39
Total deferred tax liabilities	30,319	26,401
Net deferred tax liability	$ 26,369	$ 24,205

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits, January 1	$ 1,497	$ 1,443	$ 1,441
Additions based on tax positions related to the current year	229	121	74
Additions based on tax positions related to prior years	125	319	72
Additions from acquired subsidiaries	130	0	13
Reductions for tax positions of prior years	(346)	(251)	(66)
Reductions due to expiration of statutes of limitations	(75)	(70)	(44)
Settlements with tax authorities	(17)	(65)	(47)
Gross unrecognized tax benefits, December 31	1,543	1,497	1,443
Positions paid	(531)	(688)	(340)
Liability for uncertain tax positions	$ 1,012	$ 809	$ 1,103

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net Income Attributable to Comcast Corporation	$ 2,511	$ 2,886	$ 3,216	$ 3,118	$ 14,999	$ 2,642	$ 2,521	$ 2,573	$ 11,731	$ 22,735	$ 8,678
Basic EPS attributable to Comcast Corporation shareholders (in shares)									4,584	4,708	4,819
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 0.55	$ 0.63	$ 0.70	$ 0.67	$ 3.22	$ 0.56	$ 0.53	$ 0.54	$ 2.56	$ 4.83	$ 1.80
Effect of dilutive securities:
Net Income Attributable to Comcast Corporation	$ 2,511	$ 2,886	$ 3,216	$ 3,118	$ 14,999	$ 2,642	$ 2,521	$ 2,573	$ 11,731	$ 22,735	$ 8,678
Assumed exercise or issuance of shares relating to stock plans (in shares)									56	78	56
Diluted EPS attributable to Comcast Corporation shareholders (in shares)									4,640	4,786	4,875
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 0.55	$ 0.62	$ 0.69	$ 0.66	$ 3.17	$ 0.55	$ 0.52	$ 0.53	$ 2.53	$ 4.75	$ 1.78

Long-Term Debt (Schedule of Deb

Long-Term Debt (Schedule of Debt Outstanding) (Details) £ in Millions, $ in Millions, € in Billions, ¥ in Billions, ¥ in Billions	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018JPY (¥)	Dec. 31, 2018CNY (¥)	Dec. 31, 2018EUR (€)	Dec. 31, 2017USD ($)	Dec. 31, 2017GBP (£)	Dec. 31, 2017JPY (¥)
Debt Instrument [Line Items]
Debt issuance costs, premiums and discounts, net	$ (1,702)					$ (1,943)
Total debt	111,743					64,556
Less: Current portion	4,398					5,134
Long-term debt	$ 107,345					59,422
Interest rate	3.77%	3.77%	3.77%	3.77%	3.77%
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper	$ 675					903
Interest rate	2.86%	2.86%	2.86%	2.86%	2.86%
Revolving Bank Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility	$ 606					0
Interest rate	1.13%	1.13%	1.13%	1.13%	1.13%
Term Loans [Member]
Debt Instrument [Line Items]
Term loans	$ 13,268					3,880
Interest rate	1.85%	1.85%	1.85%	1.85%	1.85%
Senior notes with maturities of 5 years or less, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 26,331					15,680
Interest rate	3.48%	3.48%	3.48%	3.48%	3.48%
Senior notes with maturities between 5 and 10 years, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 26,727					13,277
Interest rate	3.64%	3.64%	3.64%	3.64%	3.64%
Senior notes with maturities greater than 10 years, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 45,030					31,838
Interest rate	4.68%	4.68%	4.68%	4.68%	4.68%
Other Including Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Other, including capital lease obligations	$ 808					$ 921
Sky Transaction Term Loan [Member]
Debt Instrument [Line Items]
Term loans | £		£ 5,600
Universal Studios Japan Term Loans Maturing 2022 [Member]
Debt Instrument [Line Items]
Term loans | ¥			¥ 390					¥ 435
Universal Beijing Resort Term Loans [Member]
Debt Instrument [Line Items]
Term loans	569
Sky Outstanding Indebtedness [Member]
Debt Instrument [Line Items]
Current Principal Balance Debt Assumed in Acquisition Not Subject to Guarantee	10,700
Sky Outstanding Indebtedness - U.S. Dollar Denominated [Member]
Debt Instrument [Line Items]
Senior notes	$ 3,200
Sky Outstanding Indebtedness - Euro Denominated [Member]
Debt Instrument [Line Items]
Senior notes | €					€ 4.9
Sky Outstanding Indebtedness - Pounds Sterling Denominated [Member]
Debt Instrument [Line Items]
Senior notes | £		1,100
Notes 5.50% Due 2029 [Member]
Debt Instrument [Line Items]
Senior notes | £		£ 625					£ 625
Interest rate	5.50%	5.50%	5.50%	5.50%	5.50%	5.50%	5.50%	5.50%
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Debt issuance costs, premiums and discounts, net	$ (36)					$ (32)
Total debt	12,882					12,473
Less: Current portion	151					198
Long-term debt	$ 12,731					12,275
Interest rate	3.58%	3.58%	3.58%	3.58%	3.58%
NBCUniversal Media LLC [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Term loans	$ 4,122					3,860
Interest rate	1.30%	1.30%	1.30%	1.30%	1.30%
NBCUniversal Media LLC [Member] | Senior notes with maturities of 5 years or less, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 5,000					4,000
Interest rate	4.39%	4.39%	4.39%	4.39%	4.39%
NBCUniversal Media LLC [Member] | Senior notes with maturities between 5 and 10 years, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 0					1,000
Interest rate	0.00%	0.00%	0.00%	0.00%	0.00%
NBCUniversal Media LLC [Member] | Senior notes with maturities greater than 10 years, at face value [Member]
Debt Instrument [Line Items]
Senior notes	$ 2,759					2,759
Interest rate	5.50%	5.50%	5.50%	5.50%	5.50%
NBCUniversal Media LLC [Member] | 4.00% Notes Due 2049 To Comcast [Member]
Debt Instrument [Line Items]
Notes due 2049 to Comcast	$ 610					610
Interest rate	4.00%	4.00%	4.00%	4.00%	4.00%
NBCUniversal Media LLC [Member] | Other Including Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Other, including capital lease obligations	$ 427					$ 276
NBCUniversal Media LLC [Member] | Universal Studios Japan Term Loans Maturing 2022 [Member]
Debt Instrument [Line Items]
Term loans | ¥			¥ 390					¥ 435
NBCUniversal Media LLC [Member] | Universal Beijing Resort Term Loans [Member]
Debt Instrument [Line Items]
Term loans | ¥				¥ 4

Long-Term Debt (Debt Maturities

Long-Term Debt (Debt Maturities) (Details) $ in Millions	Dec. 31, 2018USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
2,019	$ 4,413
2,020	7,961
2,021	11,548
2,022	8,741
2,023	7,818
Thereafter	72,964
NBCUniversal Media LLC [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2,019	153
2,020	2,280
2,021	2,365
2,022	2,922
2,023	1,012
Thereafter	$ 4,186

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) £ in Millions, $ in Millions, ¥ in Billions	1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Feb. 28, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018JPY (¥)	Jun. 30, 2017USD ($)
Debt Instrument [Line Items]
Fair value of debt		$ 114,100	$ 114,100		$ 114,100	$ 71,700
Borrowings					44,781	11,466	$ 9,231
Repayments of debt					8,798	6,364	3,052
Amounts available under revolving credit facilities		9,200	9,200		9,200
Unused irrevocable standby letters of credit		463	463		463
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Fair value of debt		$ 13,200	$ 13,200		13,200	13,500
Borrowings					692	3,948	0
Repayments of debt					$ 438	3,498	$ 1,565
Ownership in cable holding company subsidiaries		100.00%	100.00%		100.00%			100.00%	100.00%
NBCUniversal Enterprise [Member]
Debt Instrument [Line Items]
Related party liquidation preference preferred stock not subject to guarantee		$ 725	$ 725		$ 725
NBCUniversal Enterprise [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Related party aggregate principal amount senior notes not subject to guarantee		3,000	3,000		3,000
Related party liquidation preference preferred stock not subject to guarantee		725	725		$ 725
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Borrowing margin for LIBOR based borrowings					1.00%
Senior Unsecured Fixed And Floating Rate Notes Issued October 2018 [Member]
Debt Instrument [Line Items]
Borrowings		27,000
Senior Unsecured Fixed And Floating Rate Notes Issued October 2018 [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Aggregate principal amount		27,000	27,000		$ 27,000
Comcast Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		7,600	7,600		7,600	7,000
Potential increase of maximum borrowing capacity		10,000	10,000		10,000
Amount outstanding under credit facility		0	0		0	0
NBCUniversal Enterprise Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		1,600	1,600		1,600	1,500
Potential increase of maximum borrowing capacity		2,000	2,000		2,000
Amount outstanding under credit facility		0	0		0	0
Amounts available under revolving credit facilities		942	942		942
Universal Studios Japan Term Loan Maturing March 2022 [Member]
Debt Instrument [Line Items]
Guarantee obligations, term loans		3,500	3,500		3,500				¥ 390
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper capacity										$ 7,000
Commercial paper outstanding		675	675		675	903
NBCUniversal Enterprise Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper capacity										$ 1,500
Guarantor Subsidiaries [Member]
Debt Instrument [Line Items]
Principal amount of debt securities subject to guarantee		94,200	94,200		94,200
Maturing In Next Five Years [Member]
Debt Instrument [Line Items]
Principal amount of debt securities subject to guarantee		26,900	26,900		26,900
Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount of debt securities subject to guarantee		3,000	3,000		3,000
Comcast And Comcast Cable Debt Securities [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Principal amount of debt securities subject to guarantee		86,400	86,400		86,400
Sky Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity | £								£ 1,000
Amount outstanding under credit facility		606	606		606			£ 475
Amounts available under revolving credit facilities		670	670		670
Sky Outstanding Indebtedness [Member]
Debt Instrument [Line Items]
Principal amount of debt securities not subject to guarantee		10,700	10,700		10,700
Universal Beijing Resort Term Loans [Member]
Debt Instrument [Line Items]
Principal amount of debt securities not subject to guarantee		569	569		569
Commercial Paper [Member] | NBCUniversal Enterprise [Member]
Debt Instrument [Line Items]
Commercial paper outstanding		675	675		675	0
Commercial Paper [Member] | Comcast [Member]
Debt Instrument [Line Items]
Commercial paper outstanding		0	0		0	903
Revolving Credit Facility [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Guarantee obligations, maximum capacity of credit facility		7,600	7,600		7,600
Unsecured Debt [Member] | Comcast Unsecured Sterling-Denominated Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Borrowings			8,700	£ 6,600
Unsecured Debt [Member] | Unsecured Dollar-Denominated Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Borrowings		3,000
Unsecured Debt [Member] | Senior Unsecured Fixed Rate Notes Issued February 2018 [Member]
Debt Instrument [Line Items]
Borrowings	$ 4,000
Cash Flow Hedging [Member] | Currency Swap [Member]
Debt Instrument [Line Items]
Aggregate notional amount		5,300	5,300		5,300	800
Aggregate liability fair value		23	23		23	$ 80
Net Investment Hedging [Member] | Currency Swap [Member]
Debt Instrument [Line Items]
Aggregate notional amount		$ 15,600	$ 15,600		$ 15,600

Significant Transactions (Sky T

Significant Transactions (Sky Transaction) (Details) £ / shares in Units, $ in Millions, £ in Billions	Oct. 09, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Oct. 31, 2018USD ($)	Oct. 09, 2018£ / shares
Business Acquisition [Line Items]
Debt issued to finance cash consideration							$ 44,781	$ 11,466	$ 9,231
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated weighted average useful life							16 years
Unsecured Debt [Member] | Comcast Unsecured Sterling-Denominated Term Loan Credit Agreement [Member]
Business Acquisition [Line Items]
Debt issued to finance cash consideration					$ 8,700	£ 6.6
Maximum borrowing capacity under term loans | £				£ 7		£ 7
Unsecured Debt [Member] | Comcast Unsecured Dollar-Denominated Term Loan Credit Agreement [Member]
Business Acquisition [Line Items]
Debt issued to finance cash consideration			$ 3,000
Maximum borrowing capacity under term loans										$ 3,000
Senior Notes [Member] | Comcast Senior Notes, Fixed and Floating Rates [Member]
Business Acquisition [Line Items]
Debt issued to finance cash consideration			$ 27,000
Sky Limited [Member]
Business Acquisition [Line Items]
Shares acquired, share price (in gbp per share) | £ / shares											£ 17.28
Percentage of voting interests acquired in period			100.00%	100.00%
Cash consideration	$ 39,387		$ 39,400	£ 30.2
Revenue attributable to Comcast Corporation since acquisition date		$ 4,600
Net income (loss) attributable to Comcast Corporation since acquisition date		$ 47.5
Sky Limited [Member] | Minimum [Member]
Business Acquisition [Line Items]
Estimated weighted average useful life		4 years
Sky Limited [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated weighted average useful life		18 years
Sky Limited [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Indefinite-lived intangible assets acquired	6,800
Sky Limited [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets acquired	11,800
Sky Limited [Member] | Customer Contracts [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets acquired	$ 1,800

Significant Transactions (Alloc

Significant Transactions (Allocation of Purchase Price) (Details) $ in Millions, £ in Billions	Oct. 09, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018GBP (£)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Goodwill, Acquired During Period				$ 29,925	$ 418
Sky Limited [Member]
Business Acquisition [Line Items]
Consideration transferred	$ 39,387	$ 39,400	£ 30.2
Cash	1,283
Accounts receivable and other current assets	2,405
Film and television costs (See Note 4)	2,526
Property and equipment (See Note 11)	3,386
Intangible assets (See Note 12)	20,628
Accounts payable, accrued liabilities and other current liabilities	(5,791)
Long-term debt (See Note 7)	(11,215)
Deferred tax assets (liabilities), net (See Note 5)	(1,903)
Other noncurrent assets and (liabilities), net	(1,809)
Fair value of identifiable net assets acquired	9,510
Goodwill, Acquired During Period	$ 29,877

Significant Transactions (Acqui

Significant Transactions (Acquisition-Related Costs) (Details) - Sky Limited [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Transaction expenses	$ 339
Interest expense	$ 63

Significant Transactions (Unaud

Significant Transactions (Unaudited Actual and Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Revenue	$ 109,518	$ 102,971
Net income attributable to Comcast Corporation	$ 11,365	$ 22,308
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 2.48	$ 4.74
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 2.45	$ 4.65

Significant Transactions (Unive

Significant Transactions (Universal Beijing Resort) (Details) $ in Millions, ¥ in Billions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2018CNY (¥)
Variable Interest Entity [Line Items]
Proceeds from borrowings	$ 44,781	$ 11,466	$ 9,231
Universal Beijing Resort [Member]
Variable Interest Entity [Line Items]
Ownership percentage in variable interest entity	30.00%			30.00%
Maximum borrowing capacity of variable interest entity	$ 4,000			¥ 26.6
Consolidated variable interest entity's assets included in condensed consolidated balance sheet	1,500
Consolidated variable interest entity's liabilities included in condensed consolidated balance sheet	1,000
NBCUniversal Media LLC [Member]
Variable Interest Entity [Line Items]
Proceeds from borrowings	$ 692	$ 3,948	$ 0
NBCUniversal Media LLC [Member] | Universal Beijing Resort [Member]
Variable Interest Entity [Line Items]
Ownership percentage in variable interest entity	30.00%			30.00%
Maximum borrowing capacity of variable interest entity	$ 4,000			¥ 26.6
Consolidated variable interest entity's assets included in condensed consolidated balance sheet	1,500
Consolidated variable interest entity's liabilities included in condensed consolidated balance sheet	1,000
NBCUniversal Media LLC [Member] | Universal Beijing Resort Term Loans [Member]
Variable Interest Entity [Line Items]
Proceeds from borrowings	569
Universal Beijing Resort Term Loans [Member]
Variable Interest Entity [Line Items]
Other Long-term Debt	$ 569
Universal Beijing Resort Term Loans [Member] | NBCUniversal Media LLC [Member]
Variable Interest Entity [Line Items]
Other Long-term Debt | ¥				¥ 4

Significant Transactions (FCC S

Significant Transactions (FCC Spectrum Auction) (Details) - FCC Spectrum [Member] - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Jun. 30, 2017
FCC Spectrum Auction [Line Items]
Proceeds from FCC spectrum auction	$ 482
Gain on sale of spectrum rights		$ 337
Amount of spectrum acquired		2,238		$ 2,333	$ 1,700
Deposit to acquire intangible asset			$ 1,800
NBCUniversal Media LLC [Member]
FCC Spectrum Auction [Line Items]
Proceeds from FCC spectrum auction	$ 482
Gain on sale of spectrum rights		337
Amount of spectrum acquired		$ 513		$ 608

Significant Transactions (Uni_2

Significant Transactions (Universal Studios Japan) (Details) - USD ($) $ in Millions	Apr. 06, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Payments to acquire additional interest in noncontrolling interest		$ 0	$ 2,299	$ 0
NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Payments to acquire additional interest in noncontrolling interest		$ 0	$ 2,299	$ 0
Universal Studios Japan [Member]
Business Acquisition [Line Items]
Payments to acquire additional interest in noncontrolling interest	$ 2,300
Universal Studios Japan [Member] | NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Payments to acquire additional interest in noncontrolling interest	$ 2,300

Significant Transactions (Dream

Significant Transactions (DreamWorks Animation) (Details) - USD ($) $ / shares in Units, $ in Millions	Aug. 22, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 66,154	$ 36,780	$ 35,980
NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Goodwill		$ 24,118	$ 23,989	$ 23,323
DreamWorks Animation [Member]
Business Acquisition [Line Items]
Consideration transferred	$ 3,800
Business acquisition, price paid per share (in dollars per share)	$ 41
DreamWorks Animation [Member] | NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Goodwill	$ 2,800
Film and television costs	838
DreamWorks Animation [Member] | Consideration Transferred By Comcast [Member] | NBCUniversal Media LLC [Member]
Business Acquisition [Line Items]
Consideration transferred	$ 3,800
Business acquisition, price paid per share (in dollars per share)	$ 41

Recent Accounting Pronounceme_4

Recent Accounting Pronouncements (Effect of Changes in Revenue Recognition - Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Total costs and expenses									75,498	67,011	63,905
Operating income	4,514	4,836	5,014	4,645	4,129	4,779	4,568	4,542	19,009	18,018	16,831
Net Income Attributable to Comcast Corporation	$ 2,511	$ 2,886	$ 3,216	$ 3,118	$ 14,999	$ 2,642	$ 2,521	$ 2,573	11,731	22,735	8,678
NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									35,895	32,950	31,398
Total costs and expenses									29,229	26,473	26,040
Operating income									6,666	6,477	5,358
Net Income Attributable to Comcast Corporation									$ 5,237	5,080	4,171
Previous Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										84,526	80,403
Total costs and expenses										66,539	63,544
Operating income										17,987	16,859
Net Income Attributable to Comcast Corporation										22,714	8,695
Previous Reported [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										32,997	31,593
Total costs and expenses										26,516	26,171
Operating income										6,481	5,422
Net Income Attributable to Comcast Corporation										5,084	4,235
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										503	333
Total costs and expenses										472	361
Operating income										31	(28)
Net Income Attributable to Comcast Corporation										21	(17)
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										(47)	(195)
Total costs and expenses										(43)	(131)
Operating income										(4)	(64)
Net Income Attributable to Comcast Corporation										$ (4)	$ (64)

Recent Accounting Pronounceme_5

Recent Accounting Pronouncements (Effects of Changes in Revenue Recognition - Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets	$ 21,848	$ 16,343
Film and television costs	7,837	7,087
Other intangible assets, net	38,358	18,133
Other noncurrent assets, net	5,802	4,354
Total assets	251,684	187,462
Total current liabilities	27,603	21,993
Deferred income taxes	27,589	24,259
Other noncurrent liabilities	15,329	10,972
Total equity	72,502	69,459	$ 56,163	$ 53,978
Total liabilities and equity	251,684	187,462
NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets	13,247	11,957
Film and television costs	7,292	7,082
Other noncurrent assets, net	1,822	1,804
Total assets	75,014	71,300
Total current liabilities	8,224	9,932
Other noncurrent liabilities	5,177	4,153
Total equity	46,781	43,041	$ 40,875	$ 34,303
Total liabilities and equity	$ 75,014	71,300
Previous Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets		16,060
Film and television costs		7,076
Other intangible assets, net		18,779
Other noncurrent assets, net		3,489
Total assets		186,949
Total current liabilities		21,561
Deferred income taxes		24,256
Other noncurrent liabilities		10,904
Total equity		69,449
Total liabilities and equity		186,949
Previous Reported [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets		11,673
Film and television costs		7,071
Other noncurrent assets, net		1,872
Total assets		71,073
Total current liabilities		9,602
Other noncurrent liabilities		4,109
Total equity		43,188
Total liabilities and equity		71,073
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets		283
Film and television costs		11
Other intangible assets, net		(646)
Other noncurrent assets, net		865
Total assets		513
Total current liabilities		432
Deferred income taxes		3
Other noncurrent liabilities		68
Total equity		10
Total liabilities and equity		513
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total current assets		284
Film and television costs		11
Other noncurrent assets, net		(68)
Total assets		227
Total current liabilities		330
Other noncurrent liabilities		44
Total equity		(147)
Total liabilities and equity		$ 227

Recent Accounting Pronounceme_6

Recent Accounting Pronouncements (Effect of Changes in Revenue Recognition - Cable Communications Segment) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Depreciation and Amortization									11,017	10,130	9,426
Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									55,143	53,070	50,577
Operating costs and expenses										32,002	30,563
Depreciation and Amortization										8,006	7,538
Residential, Video [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									22,455	22,874	22,204
Residential, High-Speed Internet [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									17,144	15,681	14,421
Residential, Voice [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									3,960	4,090	4,159
Business Services [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									7,129	6,437	5,705
Advertising [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									2,795	2,450	2,626
Other [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue									$ 1,660	1,538	1,462
Previous Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										84,526	80,403
Previous Reported [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										52,519	50,048
Operating costs and expenses										31,349	29,939
Depreciation and Amortization										8,143	7,670
Previous Reported [Member] | Residential, Video [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										23,129	22,357
Previous Reported [Member] | Residential, High-Speed Internet [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										14,769	13,532
Previous Reported [Member] | Residential, Voice [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										3,391	3,540
Previous Reported [Member] | Business Services [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										6,216	5,514
Previous Reported [Member] | Advertising [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										2,257	2,476
Previous Reported [Member] | Other [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										2,757	2,629
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										503	333
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										551	529
Operating costs and expenses										653	624
Depreciation and Amortization										(137)	(132)
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Residential, Video [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										(255)	(153)
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Residential, High-Speed Internet [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										912	889
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Residential, Voice [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										699	619
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Business Services [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										221	191
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Advertising [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										193	150
Effects of Adoption [Member] | Accounting Standards Update 2014-09 [Member] | Other [Member] | Cable Communications [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										$ (1,219)	$ (1,167)

Recent Accounting Pronounceme_7

Recent Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Millions	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 33
NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		0
Member's Capital [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		(232)
AOCI Attributable to Parent [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		76
AOCI Attributable to Parent [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 232
Accounting Standards Update 2016-01 [Member] | AOCI Attributable to Parent [Member] | NBCUniversal Media LLC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 232

Investments (Schedule of Invest

Investments (Schedule of Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Equity method	$ 4,035	$ 3,546
Marketable equity securities	341	433
Nonmarketable equity securities	1,805	1,186
Other investments	1,796	1,785
Total investments	7,977	6,950
Less: Current investments	94	19
Long-term Investments	7,883	6,931
NBCUniversal Media LLC [Member]
Schedule of Investments [Line Items]
Equity method	707	690
Marketable equity securities	162	430
Nonmarketable equity securities	811	696
Total investments	1,680	1,816
Long-term Investments	$ 1,680	$ 1,816

Investments (Investment Income

Investments (Investment Income (Loss), Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investment and Other Income (Loss), Net [Line Items]
Equity in net income (losses) of investees, net	$ (364)	$ 107	$ (104)
Realized and unrealized gains (losses) on equity securities, net	(187)	(17)	12
Other income (loss), net	326	331	529
Investment and other income (loss), net	(225)	421	437
NBCUniversal Media LLC [Member]
Investment and Other Income (Loss), Net [Line Items]
Equity in net income (losses) of investees, net	(371)	(201)	(99)
Realized and unrealized gains (losses) on equity securities, net	(217)	0	3
Other income (loss), net	67	57	120
Investment and other income (loss), net	$ (521)	$ (144)	$ 24

Investments (Equity Method Inve

Investments (Equity Method Investments) (Details) - USD ($) $ in Millions	Jan. 01, 2016	Apr. 30, 2018	Mar. 31, 2018	Jul. 31, 2017	Aug. 31, 2016	Jan. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 28, 2018	Jul. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments							$ 4,035	$ 3,546
Equity in net income (losses) of investees, net							364	(107)	$ 104
NBCUniversal Media LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments							707	690
Equity in net income (losses) of investees, net							371	201	99
Atairos [Member]
Schedule of Equity Method Investments [Line Items]
Term of agreement	12 years
Funding commitment	$ 4,000									$ 5,000
Management fee funding commitment	$ 40									45
Percent of losses	99.00%
Percentage of residual returns	86.00%
Equity method investments							2,700	2,400
Purchases of investments							282	994	1,200
Equity in net income (losses) of investees, net							(31)	281	(38)
Pretax gain, sale of business to Atairos		$ 200		$ 105
Atairos [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Funding commitment by management company investors										100
Atairos [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Funding commitment by management company investors										$ 50
Atairos [Member] | Former CFO [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Funding commitment by management company investors	$ 40
Hulu [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments							248	249
Equity in net income (losses) of investees, net							(454)	(276)	(168)
Cash capital contributions for equity method investments							454	300	50
Ownership percentage					30.00%						33.00%
Put/call period					3 years
Deferred gain					$ 159
Hulu [Member] | NBCUniversal Media LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments							248	249
Equity in net income (losses) of investees, net							(454)	(276)	(168)
Cash capital contributions for equity method investments							$ 454	$ 300	$ 50
Ownership percentage					30.00%						33.00%
Put/call period					3 years
Deferred gain					$ 159
Hulu [Member] | Time Warner, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage					10.00%
Hulu [Member] | Time Warner, Inc. [Member] | NBCUniversal Media LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage					10.00%
The Weather Channel [Member]
Schedule of Equity Method Investments [Line Items]
Pretax gain on sale of investment			$ 64
Pretax gain on sale of investment						$ 108
The Weather Channel [Member] | NBCUniversal Media LLC [Member]
Schedule of Equity Method Investments [Line Items]
Pretax gain on sale of investment			$ 64
Pretax gain on sale of investment						$ 108

Investments (Marketable Equity

Investments (Marketable Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Marketable Equity Securities [Line Items]
Marketable equity securities			$ 341	$ 433
NBCUniversal Media LLC [Member]
Schedule of Marketable Equity Securities [Line Items]
Contribution from member				662	$ 3,655
Marketable equity securities			162	430
Snap [Member]
Schedule of Marketable Equity Securities [Line Items]
Payments to acquire marketable securities		$ 500
Marketable equity securities			162	430
Marketable securities, recognized unrealized gains (losses)			(268)
Snap [Member] | NBCUniversal Media LLC [Member]
Schedule of Marketable Equity Securities [Line Items]
Contribution from member	$ 662
Marketable equity securities			162	$ 430
Marketable securities, recognized unrealized gains (losses)			$ (268)

Investments (Other Investments)

Investments (Other Investments) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)preferred_stock_series	Dec. 31, 2017USD ($)
Air Touch [Member]
Schedule of Other Investments [Line Items]
Number of series of preferred stock | preferred_stock_series	3
Preferred stock aggregate redemption value	$ 1,750
Redeemable subsidiary preferred shares	1,600	$ 1,600
Nonredeemable subsidiary preferred shares	100	100
Level 2 [Member] | Air Touch [Member]
Schedule of Other Investments [Line Items]
Fair value of redeemable preferred shares	$ 1,700	1,700
Air Touch [Member]
Schedule of Other Investments [Line Items]
Number of series of preferred stock | preferred_stock_series	2
Held to maturity investment	$ 1,600	1,600
Preferred stock aggregate redemption value	1,650
Air Touch [Member] | Level 2 [Member]
Schedule of Other Investments [Line Items]
Fair value of held to maturity investment redeemable preferred shares	$ 1,700	$ 1,700

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 95,743	$ 88,386
Less: Accumulated depreciation	51,306	49,916
Property and equipment, net	44,437	38,470
NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	18,183	15,512
Less: Accumulated depreciation	4,994	4,166
Property and equipment, net	$ 13,189	11,346
Cable Distribution System [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	11 years
Property and equipment, at cost	$ 38,380	36,046
Customer Premise Equipment [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	6 years
Property and equipment, at cost	$ 26,208	26,392
Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	8 years
Property and equipment, at cost	$ 12,437	10,518
Building and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	30 years
Property and equipment, at cost	$ 14,188	12,346
Building and Leasehold Improvements [Member] | NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	31 years
Property and equipment, at cost	$ 8,877	8,124
Furniture, Fixtures and Equipment [Member] | NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Weighted-Average Original Useful Life	11 years
Property and equipment, at cost	$ 5,501	4,843
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	2,991	1,752
Construction in Process [Member] | NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	2,676	1,506
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	1,539	1,332
Land [Member] | NBCUniversal Media LLC [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 1,129	$ 1,039

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Schedule of Change in Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance, beginning of period	$ 36,780	$ 35,980
Goodwill, Acquired During Period	29,925	418
Dispositions	(13)	(11)
Adjustments	(21)	186
Foreign currency translation	(517)	207
Balance, end of period	66,154	36,780
NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	23,989	23,323
Goodwill, Acquired During Period	36	273
Dispositions	(8)
Adjustments	(21)	186
Foreign currency translation	122	207
Balance, end of period	24,118	23,989
Operating Segments [Member] | Cable Communications [Member]
Goodwill [Roll Forward]
Balance, beginning of period	12,784	12,645
Goodwill, Acquired During Period	0	140
Dispositions	0	0
Adjustments	0	(1)
Foreign currency translation	0	0
Balance, end of period	12,784	12,784
Operating Segments [Member] | Cable Networks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	13,427	13,183
Goodwill, Acquired During Period	0	241
Dispositions	0	0
Adjustments	(13)	1
Foreign currency translation	(7)	2
Balance, end of period	13,407	13,427
Operating Segments [Member] | Cable Networks [Member] | NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	13,427	13,183
Goodwill, Acquired During Period	0	241
Dispositions	0
Adjustments	(13)	1
Foreign currency translation	(7)	2
Balance, end of period	13,407	13,427
Operating Segments [Member] | Broadcast Television [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	806
Goodwill, Acquired During Period	36	0
Dispositions	0	0
Adjustments	1	0
Foreign currency translation	0	0
Balance, end of period	843	806
Operating Segments [Member] | Broadcast Television [Member] | NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	806	806
Goodwill, Acquired During Period	36	0
Dispositions	0
Adjustments	1	0
Foreign currency translation	0	0
Balance, end of period	843	806
Operating Segments [Member] | Filmed Entertainment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	3,212	2,993
Goodwill, Acquired During Period	0	32
Dispositions	(8)	0
Adjustments	(9)	185
Foreign currency translation	(11)	2
Balance, end of period	3,184	3,212
Operating Segments [Member] | Filmed Entertainment [Member] | NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	3,212	2,993
Goodwill, Acquired During Period	0	32
Dispositions	(8)
Adjustments	(9)	185
Foreign currency translation	(11)	2
Balance, end of period	3,184	3,212
Operating Segments [Member] | Theme Parks [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,544	6,341
Goodwill, Acquired During Period	0	0
Dispositions	0	0
Adjustments	0	0
Foreign currency translation	140	203
Balance, end of period	6,684	6,544
Operating Segments [Member] | Theme Parks [Member] | NBCUniversal Media LLC [Member]
Goodwill [Roll Forward]
Balance, beginning of period	6,544	6,341
Goodwill, Acquired During Period	0	0
Dispositions	0
Adjustments	0	0
Foreign currency translation	140	203
Balance, end of period	6,684	6,544
Operating Segments [Member] | Sky Limited [Member]
Goodwill [Roll Forward]
Balance, beginning of period	0	0
Goodwill, Acquired During Period	29,889	0
Dispositions	0	0
Adjustments	0	0
Foreign currency translation	(639)	0
Balance, end of period	29,250	0
Corporate, Non-Segment [Member]
Goodwill [Roll Forward]
Balance, beginning of period	7	12
Goodwill, Acquired During Period	0	5
Dispositions	(5)	(11)
Adjustments	0	1
Foreign currency translation	0	0
Balance, end of period	$ 2	$ 7

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018segmentdivision
NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	4
Software [Member]
Segment Reporting Information [Line Items]
Finite-lived intangible asset amortization period	5 years
Software [Member] | NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Finite-lived intangible asset amortization period	5 years
Maximum [Member] | Software [Member]
Segment Reporting Information [Line Items]
Finite-lived intangible asset amortization period	5 years
Maximum [Member] | Software [Member] | NBCUniversal Media LLC [Member]
Segment Reporting Information [Line Items]
Finite-lived intangible asset amortization period	5 years
Cable Communications [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	1
Cable Communications [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Number of divisions | division	3

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2017
Schedule of Indefinite and Finite-Lived Intangible Assets [Line Items]
Total	$ 111,917	$ 89,448
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	(14,194)	(11,951)
Franchise Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	59,365	59,364
Trade Names [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	9,633	2,981
FCC Licenses [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,333	2,238	$ 1,700
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	16 years
Gross Carrying Amount	$ 25,046	13,612
Accumulated Amortization	$ (6,682)	(5,819)
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	5 years
Gross Carrying Amount	$ 11,395	8,258
Accumulated Amortization	$ (5,990)	(4,846)
Patents and other technology rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	7 years
Gross Carrying Amount	$ 260	259
Accumulated Amortization	$ (234)	(221)
Other agreements and rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	18 years
Gross Carrying Amount	$ 3,885	2,736
Accumulated Amortization	(1,288)	(1,065)
NBCUniversal Media LLC [Member]
Schedule of Indefinite and Finite-Lived Intangible Assets [Line Items]
Total	22,256	20,891
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	(8,590)	(7,585)
NBCUniversal Media LLC [Member] | Trade Names [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	2,981	2,981
NBCUniversal Media LLC [Member] | FCC Licenses [Member]
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 608	513
NBCUniversal Media LLC [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	19 years
Gross Carrying Amount	$ 13,269	13,301
Accumulated Amortization	$ (6,283)	(5,643)
NBCUniversal Media LLC [Member] | Software [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	5 years
Gross Carrying Amount	$ 1,779	1,516
Accumulated Amortization	$ (932)	(737)
NBCUniversal Media LLC [Member] | Other agreements and rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Original Useful Life	19 years
Gross Carrying Amount	$ 3,619	2,580
Accumulated Amortization	$ (1,375)	$ (1,205)

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets (Amortization of Intangible Assets) (Details) $ in Millions	Dec. 31, 2018USD ($)
Estimated Amortization Expense of Finite-Lived Intangible Assets
2,019	$ 3,719
2,020	3,490
2,021	3,104
2,022	2,689
2,023	2,260
NBCUniversal Media LLC [Member]
Estimated Amortization Expense of Finite-Lived Intangible Assets
2,019	1,059
2,020	1,039
2,021	936
2,022	861
2,023	$ 839

Employee Benefit Plans (Deferre

Employee Benefit Plans (Deferred Compensation Plans) (Details) - Deferred Compensation Plans [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	$ 2,885	$ 2,539	$ 2,164
Interest expense	222	209	178
NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	719	621	494
Interest expense	$ 58	$ 64	$ 48

Employee Benefit Plans (Informa

Employee Benefit Plans (Information On Our Pension Benefit Plans) (Details) - Postretirement Benefit Plan [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	$ 408	$ 425
Amounts in accumulated other comprehensive income not yet recognized in benefits expense	(439)	(458)
NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	47	51
Amounts in accumulated other comprehensive income not yet recognized in benefits expense	$ (163)	$ (177)

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash surrender value of life insurance policies	$ 351	$ 820
Expenses related to retirement investment plans	546	458	$ 446
Severance costs	243	203	315
NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expenses related to retirement investment plans	213	201	185
Severance costs	146	108	165
DreamWorks Animation [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Severance costs			61
DreamWorks Animation [Member] | NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Severance costs			61
Multiemployer Plans, Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer plan contributions	102	97	84
Multiemployer Plans, Pension [Member] | NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer plan contributions	102	97	84
Multiemployer Plans, Postretirement Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer plan contributions	183	152	136
Multiemployer Plans, Postretirement Benefit [Member] | NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer plan contributions	183	152	$ 136
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	312	338
Pension Plans [Member] | NBCUniversal Media LLC [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	$ 312	$ 338

Equity (Narrative) (Details)

Equity (Narrative) (Details) $ in Billions	12 Months Ended
	Dec. 31, 2018USD ($)vote
Equity [Line Items]
Number of votes entitled of each class B common stock | vote	15
New Authorization [Member]
Equity [Line Items]
Stock repurchase program, authorized amount	$ 12
Remaining authorized repurchase amount	$ 2
Class A Common Stock [Member]
Equity [Line Items]
Voting power	66.67%
Class B Common Stock [Member]
Equity [Line Items]
Voting power	33.33%

Equity (Changes in Common Stock

Equity (Changes in Common Stock) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class A Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares outstanding at beginning of period (in shares)	4,635,063,642	4,742,000,000	4,875,000,000
Stock compensation plans (in shares)	15,000,000	19,000,000	23,000,000
Repurchases and retirements of common stock (in shares)	(140,000,000)	(131,000,000)	(161,000,000)
Employee stock purchase plan (in shares)	7,000,000	5,000,000	5,000,000
Common stock, shares outstanding at end of period (in shares)	4,516,518,147	4,635,063,642	4,742,000,000
Class B Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares outstanding at beginning of period (in shares)	9,444,375	9,000,000	9,000,000
Stock compensation plans (in shares)	0	0	0
Repurchases and retirements of common stock (in shares)	0	0	0
Employee stock purchase plan (in shares)	0	0	0
Common stock, shares outstanding at end of period (in shares)	9,444,375	9,444,375	9,000,000

Equity (Aggregate Share Repurch

Equity (Aggregate Share Repurchases) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Cash consideration	$ 5,320	$ 5,435	$ 5,352
New Authorization [Member]
Equity, Class of Treasury Stock [Line Items]
Cash consideration	$ 5,000	$ 5,000	$ 5,000
Shares repurchased (in shares)	140	131	161

Equity (Components of Accumulat

Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Unrealized gains (losses) on marketable securities	$ 3	$ (43)
Deferred gains (losses) on cash flow hedges	55	9
Unrecognized gains (losses) on employee benefit obligations	325	260
Cumulative translation adjustments	(751)	153
Accumulated other comprehensive income (loss), net of deferred taxes	$ (368)	$ 379

Share-Based Compensation (Recog

Share-Based Compensation (Recognized Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense	$ 639	$ 586	$ 507
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense	402	349	306
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense	205	205	173
Employee stock purchase plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized share-based compensation expense	$ 32	$ 32	$ 28

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period in years		5 years
Adjustments to additional paid in capital, income tax benefit from share-based compensation		$ 75	$ 297	$ 233
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)		24
Weighted average fair value of RSUs (in dollars per share)		$ 35.56	$ 37.77	$ 30.02
Unrecognized pretax compensation expense on nonvested awards	$ 1,100	$ 1,100
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)		1 year 7 months
Restricted share units [Member] | Sky Limited [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	8
Weighted average fair value of RSUs (in dollars per share)	$ 35.38
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period from grant date that an equity-based award expires		10 years
Unrecognized pretax compensation expense on nonvested awards	$ 437	$ 437
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)		1 year 8 months 12 days

Share-Based Compensation (Stock

Share-Based Compensation (Stock Options and Restricted Share Units) (Details) shares in Millions	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	41
Weighted-average exercise price of awards granted during the year (in dollars per share) | $ / shares	$ 35.81
Stock options outstanding (in shares)	200
Weighted-average exercise price of shares outstanding (in dollars per share) | $ / shares	$ 27.69
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	24
Awards nonvested (in shares)	51
Weighted-average fair value at grant date of nonvested awards (in dollars per share) | $ / shares	$ 33.77

Share-Based Compensation (Restr

Share-Based Compensation (Restricted Share Units and Stock Option Fair Value) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option fair value (in dollars per share)	$ 7.14	$ 7.01	$ 5.78
Stock Option Valuation Assumptions:
Dividend yield	2.10%	1.70%	1.80%
Expected volatility	22.00%	20.10%	23.00%
Risk-free interest rate	2.70%	2.20%	1.50%
Expected option life	6 years	6 years 1 month 1 day	6 years 1 month 1 day
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of RSUs (in dollars per share)	$ 35.56	$ 37.77	$ 30.02

Supplemental Financial Inform_3

Supplemental Financial Information (Cash Payments for Interest and Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Payments for Interest and Income Taxes
Interest	$ 2,897	$ 2,820	$ 2,565
Income taxes	2,355	4,057	3,693
NBCUniversal Media LLC [Member]
Cash Payments for Interest and Income Taxes
Interest	408	517	548
Income taxes	$ 430	$ 282	$ 208

Supplemental Financial Inform_4

Supplemental Financial Information (Noncash Investing and Financing Activities) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Financial Information [Line Items]
Property and equipment and intangible assets accrued but not yet paid			$ 2,100	$ 1,200	$ 1,300
Dividends payable		$ 732	$ 860	$ 732	$ 653
Dividends payable (in dollars per share)		$ 0.1575	$ 0.19	$ 0.1575	$ 0.1375
Capital contribution accrued but not yet paid					$ 447
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Property and equipment and intangible assets accrued but not yet paid			$ 1,400	$ 325	$ 189
Senior Notes Exchange [Member] | Senior Notes [Member] | Comcast and NBCUniversal Senior Notes [Member]
Supplemental Financial Information [Line Items]
Aggregate principal amount issued		$ 5,500		$ 5,500
Aggregate principal amount of certain series of outstanding notes		$ 3,900
Senior Notes Exchange [Member] | Senior Notes [Member] | Comcast and NBCUniversal Senior Notes [Member] | NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Aggregate principal amount of certain series of outstanding notes	$ 3,900
Universal Beijing Resort [Member]
Supplemental Financial Information [Line Items]
Assets contributed to variable interest entity			391
Universal Beijing Resort [Member] | NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Assets contributed to variable interest entity			$ 391

Supplemental Financial Inform_5

Supplemental Financial Information (Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Financial Information [Line Items]
Cash and cash equivalents	$ 3,814	$ 3,428
Restricted cash included in other current assets	46	60
Restricted cash included in other noncurrent assets, net	49	83
Cash, cash equivalents and restricted cash, end of year	3,909	3,571	$ 3,415	$ 2,423
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Cash and cash equivalents	1,444	2,347
Restricted cash included in other noncurrent assets, net	20	30
Cash, cash equivalents and restricted cash, end of year	$ 1,464	$ 2,377	$ 1,987	$ 1,420

Supplemental Financial Inform_6

Supplemental Financial Information Supplemental Financial Information (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on marketable securities	$ 3	$ (43)
Deferred gains (losses) on cash flow hedges	55	9
Unrecognized gains (losses) on employee benefit obligations	325	260
Cumulative translation adjustments	(751)	153
Accumulated other comprehensive income (loss)	(368)	379
NBCUniversal Media LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on marketable securities	0	(233)
Deferred gains (losses) on cash flow hedges	12	10
Unrecognized gains (losses) on employee benefit obligations	140	126
Cumulative translation adjustments	102	77
Accumulated other comprehensive income (loss)	$ 254	$ (20)

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)employee	Dec. 31, 2017USD ($)
Commitment And Contingencies [Line Items]
Carrying value of contractual obligation	$ 1,100
Contractual value of a potential obligation	1,600
Redeemable Subsidiary Preferred Stock [Member] | Level 2 [Member]
Commitment And Contingencies [Line Items]
Temporary equity, fair value of redeemable subsidiary preferred stock	741	$ 748
NBCUniversal Enterprise [Member]
Commitment And Contingencies [Line Items]
Related party liquidation preference preferred stock not subject to guarantee	$ 725
NBCUniversal Enterprise [Member] | Redeemable Subsidiary Preferred Stock [Member]
Commitment And Contingencies [Line Items]
Redeemable subsidiary preferred stock, put period	30 days
Redeemable subsidiary preferred stock, dividend rate	5.25%
Redeemable subsidiary preferred stock, call period	1 year
NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Carrying value of contractual obligation	$ 1,100
Contractual value of a potential obligation	1,600
NBCUniversal Media LLC [Member] | NBCUniversal Enterprise [Member]
Commitment And Contingencies [Line Items]
Related party liquidation preference preferred stock not subject to guarantee	$ 725
Workforce Subject to Collective Bargaining Arrangements [Member]
Commitment And Contingencies [Line Items]
Number of employees covered under collective bargaining agreements | employee	10,000
Workforce Subject to Collective Bargaining Arrangements [Member] | NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Number of employees covered under collective bargaining agreements | employee	10,000
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Commitment And Contingencies [Line Items]
Percentage of full-time equivalent employees covered by collective bargaining agreements that have expired or are schedule to expire during the next year	46.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member] | NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Percentage of full-time equivalent employees covered by collective bargaining agreements that have expired or are schedule to expire during the next year	46.00%

Commitments and Contingencies_3

Commitments and Contingencies (Minimum Annual Commitments under the Programming License Agreements and Operating Leases) (Details) $ in Millions	Dec. 31, 2018USD ($)
Programming and Talent Commitments
2,019	$ 11,741
2,020	10,468
2,021	8,865
2,022	5,193
2,023	3,060
Thereafter	17,142
Operating Leases
2,019	759
2,020	709
2,021	616
2,022	480
2,023	414
Thereafter	2,285
NBCUniversal Media LLC [Member]
Programming and Talent Commitments
2,019	5,371
2,020	5,524
2,021	3,922
2,022	4,314
2,023	2,181
Thereafter	16,549
Operating Leases
2,019	248
2,020	232
2,021	199
2,022	168
2,023	144
Thereafter	$ 1,380

Commitments and Contingencies_4

Commitments and Contingencies (Rental expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitment And Contingencies [Line Items]
Rental expense	$ 779	$ 839	$ 744
NBCUniversal Media LLC [Member]
Commitment And Contingencies [Line Items]
Rental expense	$ 286	$ 274	$ 259

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Operating income	4,514	4,836	5,014	4,645	4,129	4,779	4,568	4,542	19,009	18,018	16,831
Net income attributable to Comcast Corporation	$ 2,511	$ 2,886	$ 3,216	$ 3,118	$ 14,999	$ 2,642	$ 2,521	$ 2,573	$ 11,731	$ 22,735	$ 8,678
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 0.55	$ 0.63	$ 0.70	$ 0.67	$ 3.22	$ 0.56	$ 0.53	$ 0.54	$ 2.56	$ 4.83	$ 1.80
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	0.55	0.62	0.69	0.66	3.17	0.55	0.52	0.53	2.53	4.75	1.78
Dividends declared per common share (in dollars per share)	$ 0.19	$ 0.19	$ 0.19	$ 0.19	$ 0.1575	$ 0.1575	$ 0.1575	$ 0.1575	$ 0.76	$ 0.63	$ 0.55
Income tax benefit as a result of the impact of the 2017 tax reform					$ 12,700				$ 120	$ 12,682	$ 0

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Income Statements, Captions [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Costs and Expenses:
Programming and production									29,692	25,355	24,348
Other operating and administrative									28,094	25,449	23,840
Advertising, marketing and promotion									7,036	6,519	6,291
Depreciation									8,281	7,914	7,464
Amortization									2,736	2,216	1,962
Other operating gains									(341)	(442)	0
Total costs and expenses									75,498	67,011	63,905
Operating income	4,514	4,836	5,014	4,645	4,129	4,779	4,568	4,542	19,009	18,018	16,831
Interest expense									(3,542)	(3,086)	(2,942)
Investment and other income (loss), net									(225)	421	437
Income before income taxes									15,242	15,353	14,326
Income tax (expense) benefit									(3,380)	7,569	(5,298)
Net income									11,862	22,922	9,028
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									131	187	350
Net Income Attributable to Comcast Corporation	$ 2,511	$ 2,886	$ 3,216	$ 3,118	$ 14,999	$ 2,642	$ 2,521	$ 2,573	11,731	22,735	8,678
Comprehensive income attributable to Comcast Corporation									10,908	22,822	8,950
Elimination and Consolidation Adjustments [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									(2,372)	(2,237)	(2,116)
Costs and Expenses:
Programming and production									0	0	0
Other operating and administrative									(2,372)	(2,237)	(2,116)
Advertising, marketing and promotion									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Other operating gains									0	0	0
Total costs and expenses									(2,372)	(2,237)	(2,116)
Operating income									0	0	0
Interest expense									0	0	0
Investment and other income (loss), net									(51,236)	(77,161)	(37,441)
Income before income taxes									(51,236)	(77,161)	(37,441)
Income tax (expense) benefit									0	0	0
Net income									(51,236)	(77,161)	(37,441)
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									0	0	0
Net Income Attributable to Comcast Corporation									(51,236)	(77,161)	(37,441)
Comprehensive income attributable to Comcast Corporation									(50,328)	(76,998)	(37,656)
Comcast Parent [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									1,197	1,128	1,067
Costs and Expenses:
Programming and production									0	0	0
Other operating and administrative									947	766	813
Advertising, marketing and promotion									0	0	0
Depreciation									46	31	28
Amortization									5	6	6
Other operating gains									0	0	0
Total costs and expenses									998	803	847
Operating income									199	325	220
Interest expense									(2,644)	(2,172)	(1,941)
Investment and other income (loss), net									13,638	24,076	9,799
Income before income taxes									11,193	22,229	8,078
Income tax (expense) benefit									538	506	600
Net income									11,731	22,735	8,678
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									0	0	0
Net Income Attributable to Comcast Corporation									11,731	22,735	8,678
Comprehensive income attributable to Comcast Corporation									10,908	22,822	8,950
Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Costs and Expenses:
Programming and production									0	0	0
Other operating and administrative									0	0	0
Advertising, marketing and promotion									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Other operating gains									0	0	0
Total costs and expenses									0	0	0
Operating income									0	0	0
Interest expense									(12)	(12)	(12)
Investment and other income (loss), net									13,604	21,767	9,289
Income before income taxes									13,592	21,755	9,277
Income tax (expense) benefit									8	156	6
Net income									13,600	21,911	9,283
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									0	0	0
Net Income Attributable to Comcast Corporation									13,600	21,911	9,283
Comprehensive income attributable to Comcast Corporation									13,623	21,909	9,325
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									1,175	1,109	1,049
Costs and Expenses:
Programming and production									0	0	0
Other operating and administrative									1,175	1,109	1,049
Advertising, marketing and promotion									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Other operating gains									0	0	0
Total costs and expenses									1,175	1,109	1,049
Operating income									0	0	0
Interest expense									(190)	(207)	(239)
Investment and other income (loss), net									12,021	19,610	8,703
Income before income taxes									11,831	19,403	8,464
Income tax (expense) benefit									40	71	84
Net income									11,871	19,474	8,548
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									0	0	0
Net Income Attributable to Comcast Corporation									11,871	19,474	8,548
Comprehensive income attributable to Comcast Corporation									11,873	19,477	8,554
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Costs and Expenses:
Programming and production									0	0	0
Other operating and administrative									1,023	1,044	932
Advertising, marketing and promotion									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Other operating gains									0	0	0
Total costs and expenses									1,023	1,044	932
Operating income									(1,023)	(1,044)	(932)
Interest expense									(430)	(456)	(456)
Investment and other income (loss), net									6,694	6,584	5,572
Income before income taxes									5,241	5,084	4,184
Income tax (expense) benefit									(4)	(4)	(13)
Net income									5,237	5,080	4,171
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									0	0	0
Net Income Attributable to Comcast Corporation									5,237	5,080	4,171
Comprehensive income attributable to Comcast Corporation									5,279	5,054	4,248
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									94,507	85,029	80,736
Costs and Expenses:
Programming and production									29,692	25,355	24,348
Other operating and administrative									27,321	24,767	23,162
Advertising, marketing and promotion									7,036	6,519	6,291
Depreciation									8,235	7,883	7,436
Amortization									2,731	2,210	1,956
Other operating gains									(341)	(442)	0
Total costs and expenses									74,674	66,292	63,193
Operating income									19,833	18,737	17,543
Interest expense									(266)	(239)	(294)
Investment and other income (loss), net									5,054	5,545	4,515
Income before income taxes									24,621	24,043	21,764
Income tax (expense) benefit									(3,962)	6,840	(5,975)
Net income									20,659	30,883	15,789
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock									131	187	350
Net Income Attributable to Comcast Corporation									20,528	30,696	15,439
Comprehensive income attributable to Comcast Corporation									19,553	30,558	15,529
Service [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									94,507	85,029	80,736
Service [Member] | Elimination and Consolidation Adjustments [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Service [Member] | Comcast Parent [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Service [Member] | Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Service [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Service [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Service [Member] | Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									94,507	85,029	80,736
Management Fee [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Management Fee [Member] | Elimination and Consolidation Adjustments [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									(2,372)	(2,237)	(2,116)
Management Fee [Member] | Comcast Parent [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									1,197	1,128	1,067
Management Fee [Member] | Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Management Fee [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									1,175	1,109	1,049
Management Fee [Member] | Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Management Fee [Member] | Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									$ 0	$ 0	$ 0

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net cash provided by operating activities	$ 24,297	$ 21,261	$ 19,691
Investing Activities
Net transactions with affiliates	0	0	0
Capital expenditures	(9,774)	(9,550)	(9,135)
Cash paid for intangible assets	(1,935)	(1,605)	(1,552)
Acquisitions and construction of real estate properties	(143)	(418)	(428)
Construction of Universal Beijing Resort	(460)	(71)	(22)
Acquisitions, net of cash acquired	(38,219)	(532)	(3,929)
Proceeds from sales of businesses and investments	141	150	218
Purchases of investments	(1,257)	(2,292)	(1,697)
Deposits	0	0	(1,749)
Other	793	785	29
Net cash provided by (used in) investing activities	(50,854)	(13,533)	(18,265)
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	379	(1,905)	1,790
Proceeds from borrowings	44,781	11,466	9,231
Repurchases and repayments of debt	(8,798)	(6,364)	(3,052)
Repurchases of common stock under repurchase program and employee plans	(5,320)	(5,435)	(5,352)
Dividends paid	(3,352)	(2,883)	(2,601)
Purchase of Universal Studios Japan noncontrolling interests	0	(2,299)	0
Issuances of common stock	0	0	23
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	(277)	(252)	(253)
Other	(273)	100	(220)
Net cash provided by (used in) financing activities	27,140	(7,572)	(434)
Impact of foreign currency on cash, cash equivalents and restricted cash	(245)	0	0
Increase (decrease) in cash and cash equivalents and restricted cash	338	156	992
Cash, cash equivalents and restricted cash, beginning of year	3,571	3,415	2,423
Cash, cash equivalents and restricted cash, end of year	3,909	3,571	3,415
Elimination and Consolidation Adjustments [Member]
Operating Activities
Net cash provided by operating activities	0	0	0
Investing Activities
Net transactions with affiliates	0	0	0
Capital expenditures	0	0	0
Cash paid for intangible assets	0	0	0
Acquisitions and construction of real estate properties	0	0	0
Construction of Universal Beijing Resort	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sales of businesses and investments	0	0	0
Purchases of investments	0	0	0
Deposits	0	0	0
Other	0	0	0
Net cash provided by (used in) investing activities	0	0	0
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	0	0	0
Proceeds from borrowings	0	0	0
Repurchases and repayments of debt	0	0	0
Repurchases of common stock under repurchase program and employee plans	0	0	0
Dividends paid	0	0	0
Purchase of Universal Studios Japan noncontrolling interests	0	0
Issuances of common stock	0	0	0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Impact of foreign currency on cash, cash equivalents and restricted cash	0
Increase (decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash, beginning of year	0	0	0
Cash, cash equivalents and restricted cash, end of year	0	0	0
Comcast Parent [Member] | Reportable Legal Entities [Member]
Operating Activities
Net cash provided by operating activities	(2,245)	151	349
Investing Activities
Net transactions with affiliates	(26,179)	5,578	(1,956)
Capital expenditures	(27)	(12)	(13)
Cash paid for intangible assets	(4)	(4)	(9)
Acquisitions and construction of real estate properties	(105)	(267)	(35)
Construction of Universal Beijing Resort	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sales of businesses and investments	0	0	0
Purchases of investments	(126)	(70)	(40)
Deposits	0	0	0
Other	148	101	(108)
Net cash provided by (used in) investing activities	(26,293)	5,326	(2,161)
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	(902)	(837)	1,339
Proceeds from borrowings	44,113	5,997	9,231
Repurchases and repayments of debt	(5,737)	(2,288)	(750)
Repurchases of common stock under repurchase program and employee plans	(5,320)	(5,435)	(5,352)
Dividends paid	(3,352)	(2,883)	(2,601)
Purchase of Universal Studios Japan noncontrolling interests	0	0
Issuances of common stock	0	0	23
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	0	0	0
Other	(201)	(31)	(78)
Net cash provided by (used in) financing activities	28,601	(5,477)	1,812
Impact of foreign currency on cash, cash equivalents and restricted cash	(63)
Increase (decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash, beginning of year	0	0	0
Cash, cash equivalents and restricted cash, end of year	0	0	0
Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member]
Operating Activities
Net cash provided by operating activities	126	15	(336)
Investing Activities
Net transactions with affiliates	(575)	(5)	336
Capital expenditures	0	0	0
Cash paid for intangible assets	0	0	0
Acquisitions and construction of real estate properties	0	0	0
Construction of Universal Beijing Resort	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sales of businesses and investments	0	0	0
Purchases of investments	0	(10)	0
Deposits	0	0	0
Other	449	0	0
Net cash provided by (used in) investing activities	(126)	(15)	336
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	0	0	0
Proceeds from borrowings	0	0	0
Repurchases and repayments of debt	0	0	0
Repurchases of common stock under repurchase program and employee plans	0	0	0
Dividends paid	0	0	0
Purchase of Universal Studios Japan noncontrolling interests	0	0
Issuances of common stock	0	0	0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Impact of foreign currency on cash, cash equivalents and restricted cash	0
Increase (decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash, beginning of year	0	0	0
Cash, cash equivalents and restricted cash, end of year	0	0	0
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member]
Operating Activities
Net cash provided by operating activities	(112)	(147)	(100)
Investing Activities
Net transactions with affiliates	112	757	100
Capital expenditures	0	0	0
Cash paid for intangible assets	0	0	0
Acquisitions and construction of real estate properties	0	0	0
Construction of Universal Beijing Resort	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sales of businesses and investments	0	0	0
Purchases of investments	0	(60)	0
Deposits	0	0	0
Other	0	0	0
Net cash provided by (used in) investing activities	112	697	100
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	0	0	0
Proceeds from borrowings	0	0	0
Repurchases and repayments of debt	0	(550)	0
Repurchases of common stock under repurchase program and employee plans	0	0	0
Dividends paid	0	0	0
Purchase of Universal Studios Japan noncontrolling interests	0	0
Issuances of common stock	0	0	0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	0	(550)	0
Impact of foreign currency on cash, cash equivalents and restricted cash	0
Increase (decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash, cash equivalents and restricted cash, beginning of year	0	0	0
Cash, cash equivalents and restricted cash, end of year	0	0	0
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member]
Operating Activities
Net cash provided by operating activities	(1,430)	(1,439)	(1,453)
Investing Activities
Net transactions with affiliates	1,336	1,447	2,642
Capital expenditures	0	0	0
Cash paid for intangible assets	0	0	0
Acquisitions and construction of real estate properties	0	0	0
Construction of Universal Beijing Resort	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sales of businesses and investments	68	14	104
Purchases of investments	(50)	(62)	(210)
Deposits	0	0	0
Other	0	58	(35)
Net cash provided by (used in) investing activities	1,354	1,457	2,501
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	0	0	0
Proceeds from borrowings	0	0	0
Repurchases and repayments of debt	(4)	(4)	(1,005)
Repurchases of common stock under repurchase program and employee plans	0	0	0
Dividends paid	0	0	0
Purchase of Universal Studios Japan noncontrolling interests	0	0
Issuances of common stock	0	0	0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	0	0	0
Other	0	0	25
Net cash provided by (used in) financing activities	(4)	(4)	(980)
Impact of foreign currency on cash, cash equivalents and restricted cash	0
Increase (decrease) in cash and cash equivalents and restricted cash	(80)	14	68
Cash, cash equivalents and restricted cash, beginning of year	496	482	414
Cash, cash equivalents and restricted cash, end of year	416	496	482
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Operating Activities
Net cash provided by operating activities	27,958	22,681	21,231
Investing Activities
Net transactions with affiliates	25,306	(7,777)	(1,122)
Capital expenditures	(9,747)	(9,538)	(9,122)
Cash paid for intangible assets	(1,931)	(1,601)	(1,543)
Acquisitions and construction of real estate properties	(38)	(151)	(393)
Construction of Universal Beijing Resort	(460)	(71)	(22)
Acquisitions, net of cash acquired	(38,219)	(532)	(3,929)
Proceeds from sales of businesses and investments	73	136	114
Purchases of investments	(1,081)	(2,090)	(1,447)
Deposits	0	0	(1,749)
Other	196	626	172
Net cash provided by (used in) investing activities	(25,901)	(20,998)	(19,041)
Financing Activities
Proceeds from (repayments of) short-term borrowings, net	1,281	(1,068)	451
Proceeds from borrowings	668	5,469	0
Repurchases and repayments of debt	(3,057)	(3,522)	(1,297)
Repurchases of common stock under repurchase program and employee plans	0	0	0
Dividends paid	0	0	0
Purchase of Universal Studios Japan noncontrolling interests	0	(2,299)
Issuances of common stock	0	0	0
Distributions to noncontrolling interests and dividends for redeemable subsidiary preferred stock	(277)	(252)	(253)
Other	(72)	131	(167)
Net cash provided by (used in) financing activities	(1,457)	(1,541)	(1,266)
Impact of foreign currency on cash, cash equivalents and restricted cash	(182)
Increase (decrease) in cash and cash equivalents and restricted cash	418	142	924
Cash, cash equivalents and restricted cash, beginning of year	3,075	2,933	2,009
Cash, cash equivalents and restricted cash, end of year	$ 3,493	$ 3,075	$ 2,933

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 3,814	$ 3,428
Receivables, net	11,104	8,834
Programming rights	3,746	1,613
Other current assets	3,184	2,468
Total current assets	21,848	16,343
Film and television costs	7,837	7,087
Investments	7,883	6,931
Investments in and amounts due from subsidiaries eliminated upon consolidation	0	0
Property and equipment, net	44,437	38,470
Franchise rights	59,365	59,364
Goodwill	66,154	36,780	$ 35,980
Other intangible assets, net	38,358	18,133
Other noncurrent assets, net	5,802	4,354
Total assets	251,684	187,462
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	8,494	6,908
Accrued participations and residuals	1,808	1,644
Deferred revenue	2,182	1,687
Accrued expenses and other current liabilities	10,721	6,620
Current portion of long-term debt	4,398	5,134
Total current liabilities	27,603	21,993
Long-term debt, less current portion	107,345	59,422
Deferred income taxes	27,589	24,259
Other noncurrent liabilities	15,329	10,972
Redeemable noncontrolling interests	1,316	1,357
Equity:
Common stock	54	55
Other shareholders’ equity	71,559	68,561
Total Comcast Corporation shareholders’ equity	71,613	68,616
Noncontrolling interests	889	843
Total equity	72,502	69,459	$ 56,163	$ 53,978
Total liabilities and equity	251,684	187,462
Elimination and Consolidation Adjustments [Member]
Assets
Cash and cash equivalents	0	0
Receivables, net	0	0
Programming rights	0	0
Other current assets	0	0
Total current assets	0	0
Film and television costs	0	0
Investments	0	0
Investments in and amounts due from subsidiaries eliminated upon consolidation	(586,231)	(562,645)
Property and equipment, net	0	0
Franchise rights	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Other noncurrent assets, net	(458)	(314)
Total assets	(586,689)	(562,959)
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	0	0
Accrued participations and residuals	0	0
Deferred revenue	0	0
Accrued expenses and other current liabilities	0	0
Current portion of long-term debt	0	0
Total current liabilities	0	0
Long-term debt, less current portion	0	0
Deferred income taxes	(524)	(343)
Other noncurrent liabilities	66	29
Redeemable noncontrolling interests	0	0
Equity:
Common stock	0	0
Other shareholders’ equity	(586,231)	(562,645)
Total Comcast Corporation shareholders’ equity	(586,231)	(562,645)
Noncontrolling interests	0	0
Total equity	(586,231)	(562,645)
Total liabilities and equity	(586,689)	(562,959)
Comcast Parent [Member] | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	0	0
Receivables, net	0	0
Programming rights	0	0
Other current assets	66	60
Total current assets	66	60
Film and television costs	0	0
Investments	270	146
Investments in and amounts due from subsidiaries eliminated upon consolidation	157,264	117,164
Property and equipment, net	670	551
Franchise rights	0	0
Goodwill	0	0
Other intangible assets, net	11	12
Other noncurrent assets, net	1,057	435
Total assets	159,338	118,368
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	2	16
Accrued participations and residuals	0	0
Deferred revenue	0	0
Accrued expenses and other current liabilities	2,357	1,888
Current portion of long-term debt	699	2,810
Total current liabilities	3,058	4,714
Long-term debt, less current portion	81,661	42,428
Deferred income taxes	0	0
Other noncurrent liabilities	3,006	2,610
Redeemable noncontrolling interests	0	0
Equity:
Common stock	54	55
Other shareholders’ equity	71,559	68,561
Total Comcast Corporation shareholders’ equity	71,613	68,616
Noncontrolling interests	0	0
Total equity	71,613	68,616
Total liabilities and equity	159,338	118,368
Subsidiary Issuer [Member] | Reportable Legal Entities [Member] | Comcast Holdings [Member]
Assets
Cash and cash equivalents	0	0
Receivables, net	0	0
Programming rights	0	0
Other current assets	20	0
Total current assets	20	0
Film and television costs	0	0
Investments	11	21
Investments in and amounts due from subsidiaries eliminated upon consolidation	147,028	142,519
Property and equipment, net	0	0
Franchise rights	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Other noncurrent assets, net	208	708
Total assets	147,267	143,248
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	0	0
Accrued participations and residuals	0	0
Deferred revenue	0	0
Accrued expenses and other current liabilities	150	92
Current portion of long-term debt	0	0
Total current liabilities	150	92
Long-term debt, less current portion	146	140
Deferred income taxes	314	285
Other noncurrent liabilities	0	0
Redeemable noncontrolling interests	0	0
Equity:
Common stock	0	0
Other shareholders’ equity	146,657	142,731
Total Comcast Corporation shareholders’ equity	146,657	142,731
Noncontrolling interests	0	0
Total equity	146,657	142,731
Total liabilities and equity	147,267	143,248
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | CCCL Parent [Member]
Assets
Cash and cash equivalents	0	0
Receivables, net	0	0
Programming rights	0	0
Other current assets	0	7
Total current assets	0	7
Film and television costs	0	0
Investments	143	108
Investments in and amounts due from subsidiaries eliminated upon consolidation	130,214	139,528
Property and equipment, net	0	0
Franchise rights	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Other noncurrent assets, net	0	0
Total assets	130,357	139,643
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	0	0
Accrued participations and residuals	0	0
Deferred revenue	0	0
Accrued expenses and other current liabilities	360	333
Current portion of long-term debt	0	0
Total current liabilities	360	333
Long-term debt, less current portion	2,100	2,100
Deferred income taxes	0	0
Other noncurrent liabilities	0	0
Redeemable noncontrolling interests	0	0
Equity:
Common stock	0	0
Other shareholders’ equity	127,897	137,210
Total Comcast Corporation shareholders’ equity	127,897	137,210
Noncontrolling interests	0	0
Total equity	127,897	137,210
Total liabilities and equity	130,357	139,643
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member] | NBCUniversal Media Parent [Member]
Assets
Cash and cash equivalents	416	496
Receivables, net	0	0
Programming rights	0	0
Other current assets	28	25
Total current assets	444	521
Film and television costs	0	0
Investments	790	693
Investments in and amounts due from subsidiaries eliminated upon consolidation	53,853	50,102
Property and equipment, net	0	0
Franchise rights	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Other noncurrent assets, net	85	88
Total assets	55,172	51,404
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	0	0
Accrued participations and residuals	0	0
Deferred revenue	0	0
Accrued expenses and other current liabilities	282	326
Current portion of long-term debt	4	4
Total current liabilities	286	330
Long-term debt, less current portion	7,748	7,751
Deferred income taxes	65	67
Other noncurrent liabilities	1,201	1,128
Redeemable noncontrolling interests	0	0
Equity:
Common stock	0	0
Other shareholders’ equity	45,872	42,128
Total Comcast Corporation shareholders’ equity	45,872	42,128
Noncontrolling interests	0	0
Total equity	45,872	42,128
Total liabilities and equity	55,172	51,404
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	3,398	2,932
Receivables, net	11,104	8,834
Programming rights	3,746	1,613
Other current assets	3,070	2,376
Total current assets	21,318	15,755
Film and television costs	7,837	7,087
Investments	6,669	5,963
Investments in and amounts due from subsidiaries eliminated upon consolidation	97,872	113,332
Property and equipment, net	43,767	37,919
Franchise rights	59,365	59,364
Goodwill	66,154	36,780
Other intangible assets, net	38,347	18,121
Other noncurrent assets, net	4,910	3,437
Total assets	346,239	297,758
Liabilities and Equity
Accounts payable and accrued expenses related to trade creditors	8,492	6,892
Accrued participations and residuals	1,808	1,644
Deferred revenue	2,182	1,687
Accrued expenses and other current liabilities	7,572	3,981
Current portion of long-term debt	3,695	2,320
Total current liabilities	23,749	16,524
Long-term debt, less current portion	15,690	7,003
Deferred income taxes	27,734	24,250
Other noncurrent liabilities	11,056	7,205
Redeemable noncontrolling interests	1,316	1,357
Equity:
Common stock	0	0
Other shareholders’ equity	265,805	240,576
Total Comcast Corporation shareholders’ equity	265,805	240,576
Noncontrolling interests	889	843
Total equity	266,694	241,419
Total liabilities and equity	$ 346,239	$ 297,758

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - USD ($) $ in Millions	Mar. 01, 2018	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016
Related Party Transaction [Line Items]
Other noncurrent liabilities			$ 10,972	$ 15,329	$ 10,972
Interest expense on extinguishment of debt				3,542	3,086	$ 2,942
Recognized share-based compensation expense				639	586	507
Restricted share units [Member]
Related Party Transaction [Line Items]
Recognized share-based compensation expense				402	349	306
Unrecognized pretax compensation expense on nonvested awards				$ 1,100
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)				1 year 7 months
Stock options [Member]
Related Party Transaction [Line Items]
Recognized share-based compensation expense				$ 205	205	173
Unrecognized pretax compensation expense on nonvested awards				$ 437
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)				1 year 8 months 12 days
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Other noncurrent liabilities			4,153	$ 5,177	4,153
Interest expense on extinguishment of debt				489	727	595
Recognized share-based compensation expense				151	133	$ 99
NBCUniversal Media LLC [Member] | Restricted share units [Member]
Related Party Transaction [Line Items]
Unrecognized pretax compensation expense on nonvested awards				$ 270
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)				1 year 7 months
NBCUniversal Media LLC [Member] | Stock options [Member]
Related Party Transaction [Line Items]
Unrecognized pretax compensation expense on nonvested awards				$ 23
Unrecognized pretax compensation expense on nonvested awards, weighted average period of recognition (in years)				1 year
NBCUniversal Media LLC [Member] | Carrying Value Of Related Party Contractual Obligation [Member]
Related Party Transaction [Line Items]
Other noncurrent liabilities				$ 383
NBCUniversal Media LLC [Member] | NBCUniversal Holdings Preferred Stock [Member]
Related Party Transaction [Line Items]
Preferred stock, dividend rate				8.25%
Preferred stock liquidation preference value				$ 9,400
Preferred stock dividend rate, spread on variable rate	7.44%
NBCUniversal Media LLC [Member] | Former Comcast And NBCUniversal Revolving Credit Agreements [Member]
Related Party Transaction [Line Items]
Revolving credit agreement capacity							$ 3,000
NBCUniversal Media LLC [Member] | Comcast and NBCUniversal Revolving Credit Agreements [Member]
Related Party Transaction [Line Items]
Revolving credit agreement capacity							$ 5,000
Borrowing margin for LIBOR based borrowings				1.00%
Senior Notes Exchange [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Interest expense on extinguishment of debt		$ 157
Senior Notes Exchange [Member] | Senior Notes [Member] | Senior 3.97% Notes Due 2047 [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Aggregate principal amount		$ 2,000
Interest rate		3.97%
Senior Notes Exchange [Member] | Senior Notes [Member] | Senior 4.00% Notes Due 2047 [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Aggregate principal amount		$ 2,000
Interest rate		4.00%
Senior Notes Exchange [Member] | Senior Notes [Member] | Senior 4.00% Notes Due 2047 [Member] | Comcast [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Aggregate principal amount		$ 610
Interest rate		4.00%
Senior Notes Exchange [Member] | Senior Notes [Member] | Senior 4.05% Notes Due 2052 [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Aggregate principal amount		$ 1,500
Interest rate		4.05%
Senior Notes Exchange [Member] | Senior Notes [Member] | Comcast and NBCUniversal Senior Notes [Member]
Related Party Transaction [Line Items]
Aggregate principal amount			5,500		$ 5,500
Amount of debt exchanged			$ 3,900
Senior Notes Exchange [Member] | Senior Notes [Member] | Comcast and NBCUniversal Senior Notes [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Amount of debt exchanged		$ 3,900
Senior Notes Exchange [Member] | Senior Notes [Member] | Senior 6.40% Notes Due 2040 [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Interest rate		6.40%
Amount of debt exchanged		$ 442

Related Party Transactions (Con

Related Party Transactions (Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Receivables, net	$ 11,104	$ 8,834
Accounts payable and accrued expenses related to trade creditors	8,494	6,908
Accrued expenses and other current liabilities	10,721	6,620
Long-term debt, less current portion	107,345	59,422
Other noncurrent liabilities	15,329	10,972
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Receivables, net	7,293	6,967
Note receivable from Comcast	2,054	0
Accounts payable and accrued expenses related to trade creditors	1,933	1,663
Accrued expenses and other current liabilities	2,195	2,394
Note payable to Comcast	54	1,831
Long-term debt, less current portion	12,731	12,275
Other noncurrent liabilities	5,177	4,153
Comcast And Consolidated Subsidiaries [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Receivables, net	464	326
Note receivable from Comcast	2,054	0
Accounts payable and accrued expenses related to trade creditors	78	54
Accrued expenses and other current liabilities	32	50
Note payable to Comcast	54	1,831
Long-term debt, less current portion	701	610
Other noncurrent liabilities	$ 410	$ 389

Related Party Transactions (C_2

Related Party Transactions (Condensed Consolidated Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Revenue	$ 27,846	$ 22,135	$ 21,735	$ 22,791	$ 22,075	$ 21,081	$ 21,286	$ 20,587	$ 94,507	$ 85,029	$ 80,736
Total costs and expenses									(75,498)	(67,011)	(63,905)
NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Revenue									35,895	32,950	31,398
Total costs and expenses									(29,229)	(26,473)	(26,040)
Comcast And Consolidated Subsidiaries [Member] | NBCUniversal Media LLC [Member]
Related Party Transaction [Line Items]
Revenue									2,156	1,837	1,742
Total costs and expenses									(245)	(214)	(220)
Interest expense and investment and other income (loss), net									$ (54)	$ (250)	$ (69)

Schedule II Valuation and Qua_2

Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 288	$ 250	$ 226
Additions Charged to Costs and Expenses	616	554	558
Deductions from Reserves	552	516	534
Balance at End of Year	352	288	250
Allowance for doubtful accounts [Member] | NBCUniversal Media LLC [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	88	84	69
Additions Charged to Costs and Expenses	32	23	26
Deductions from Reserves	21	19	11
Balance at End of Year	99	88	84
Valuation allowance on deferred tax assets [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	377	266	342
Additions Charged to Costs and Expenses	367	111	23
Deductions from Reserves	112	0	99
Balance at End of Year	632	377	266
Valuation allowance on deferred tax assets [Member] | NBCUniversal Media LLC [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	87	72	71
Additions Charged to Costs and Expenses	13	15	23
Deductions from Reserves	27	0	22
Balance at End of Year	$ 73	$ 87	$ 72