Centene (CNC) 10-Q 24 Oct 17 2017 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 13, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	CENTENE CORP
Entity Central Index Key	1,071,739
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		172,566,531

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 4,281	$ 3,930
Premium and related receivables	3,955	3,098
Short-term investments	595	505
Other current assets	829	832
Total current assets	9,660	8,365
Long-term investments	4,927	4,545
Restricted deposits	138	138
Property, software and equipment, net	1,003	797
Goodwill	4,712	4,712
Intangible assets, net	1,428	1,545
Other long-term assets	132	95
Total assets	22,000	20,197
Current liabilities:
Medical claims liability	4,333	3,929
Accounts payable and accrued expenses	4,804	4,377
Unearned revenue	568	313
Current portion of long-term debt	4	4
Total current liabilities	9,709	8,623
Long-term debt	4,717	4,651
Other long-term liabilities	901	869
Total liabilities	15,327	14,143
Commitments and contingencies
Redeemable noncontrolling interests	20	145
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized 10,000 shares; no shares issued or outstanding at September 30, 2017 and December 31, 2016	0	0
Common stock, $0.001 par value; authorized 400,000 shares; 179,033 issued and 172,566 outstanding at September 30, 2017, and 178,134 issued and 171,919 outstanding at December 31, 2016	0	0
Additional paid-in capital	4,310	4,190
Accumulated other comprehensive earnings (loss)	9	(36)
Retained earnings	2,518	1,920
Treasury stock, at cost (6,467 and 6,215 shares, respectively)	(197)	(179)
Total Centene stockholders’ equity	6,640	5,895
Noncontrolling interest	13	14
Total stockholders’ equity	6,653	5,909
Total liabilities, redeemable noncontrolling interests and stockholders’ equity	$ 22,000	$ 20,197

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Sep. 30, 2017	Dec. 31, 2016
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	400,000	400,000
Common stock, shares issued	179,033	178,134
Common stock, shares outstanding	172,566	171,919
Treasury stock (in shares)	6,467	6,215

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Premium	$ 10,850	$ 9,625	$ 32,393	$ 25,299
Service	571	590	1,634	1,603
Premium and service revenues	11,421	10,215	34,027	26,902
Premium tax and health insurer fee	477	631	1,549	1,794
Total revenues	11,898	10,846	35,576	28,696
Expenses:
Medical costs	9,543	8,376	28,278	22,072
Cost of services	437	504	1,334	1,386
Selling, general and administrative expenses	1,030	940	3,186	2,611
Amortization of acquired intangible assets	38	43	117	95
Premium tax expense	510	512	1,643	1,460
Health insurer fee expense	0	129	0	333
Total operating expenses	11,558	10,504	34,558	27,957
Earnings from operations	340	342	1,018	739
Other income (expense):
Investment and other income	51	33	137	80
Interest expense	(65)	(57)	(189)	(142)
Earnings from continuing operations, before income tax expense	326	318	966	677
Income tax expense	125	169	381	372
Earnings from continuing operations, net of income tax expense	201	149	585	305
Discontinued operations, net of income tax benefit	0	(1)	0	(3)
Net earnings	201	148	585	302
(Earnings) loss attributable to noncontrolling interests	4	(1)	13	(1)
Net earnings	205	147	598	301
Amounts attributable to Centene Corporation common shareholders:
Earnings from continuing operations, net of income tax expense	205	148	598	304
Discontinued operations, net of income tax benefit	0	(1)	0	(3)
Net earnings	$ 205	$ 147	$ 598	$ 301
Basic:
Continuing operations (in dollars per share)	$ 1.19	$ 0.87	$ 3.47	$ 1.95
Discontinued operations (in dollars per share)	0	(0.01)	0	(0.02)
Basic earnings per common share (in dollars per share)	1.19	0.86	3.47	1.93
Diluted:
Continuing operations (in dollars per share)	1.16	0.84	3.39	1.90
Discontinued operations (in dollars per share)	0	0	0	(0.02)
Diluted earnings per common share (in dollars per share)	$ 1.16	$ 0.84	$ 3.39	$ 1.88

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Earnings - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net earnings	$ 201	$ 148	$ 585	$ 302
Reclassification adjustment, net of tax	0	(1)	(1)	0
Change in unrealized gain on investments, net of tax	7	5	41	57
Foreign currency translation adjustments	1	(1)	5	(1)
Other comprehensive earnings	8	3	45	56
Comprehensive earnings	209	151	630	358
Comprehensive (earnings) loss attributable to noncontrolling interests	4	(1)	13	(1)
Comprehensive earnings attributable to Centene Corporation	$ 213	$ 150	$ 643	$ 357

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2017 - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Earnings (Loss)	Retained Earnings	Treasury Stock	Non- controlling Interest
Balance at Dec. 31, 2016	$ 5,909	$ 0	$ 4,190	$ (36)	$ 1,920	$ (179)	$ 14
Balance (in shares) at Dec. 31, 2016	171,919	178,134
Treasury stock (in shares) at Dec. 31, 2016	6,215					6,215
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	$ 597				598		(1)
Other comprehensive earnings, net of $23 tax	45			45
Common stock issued for employee benefit plans	8	$ 0	8
Common stock issued for employee benefit plans (in shares)		899
Common stock repurchases	(18)					$ (18)
Common stock repurchases (in shares)						252
Stock compensation expense	99		99
Purchase of noncontrolling interest	13		13
Balance at Sep. 30, 2017	$ 6,653	$ 0	$ 4,310	$ 9	$ 2,518	$ (197)	$ 13
Balance (in shares) at Sep. 30, 2017	172,566	179,033
Treasury stock (in shares) at Sep. 30, 2017	6,467

Consolidated Statement of Stoc7

Consolidated Statement of Stockholders' Equity (Parenthetical) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Other comprehensive earnings, tax	$ 23
Common stock
Common stock, par value (in dollars per share)	$ 0.001	0.001
Treasury Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net earnings	$ 585	$ 302
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation and amortization	264	189
Stock compensation expense	99	112
Deferred income taxes	(32)	(17)
Changes in assets and liabilities
Premium and related receivables	(749)	(906)
Other assets	(39)	7
Medical claims liabilities	406	15
Unearned revenue	255	301
Accounts payable and accrued expenses	205	99
Other long-term liabilities	45	156
Other operating activities, net	0	1
Net cash provided by operating activities	1,039	259
Cash flows from investing activities:
Capital expenditures	(301)	(211)
Purchases of investments	(1,720)	(1,528)
Sales and maturities of investments	1,335	955
Investments in acquisitions, net of cash acquired	0	(848)
Net cash used in investing activities	(686)	(1,632)
Cash flows from financing activities:
Proceeds from long-term debt	1,170	6,956
Payments of long-term debt	(1,124)	(4,257)
Common stock repurchases	(18)	(29)
Purchase of noncontrolling interest	(33)	(14)
Debt issuance costs	0	(59)
Other financing activities, net	2	(3)
Net cash (used in) provided by financing activities	(3)	2,594
Effect of exchange rate changes on cash and cash equivalents	1	1
Net increase in cash and cash equivalents	351	1,222
Cash and cash equivalents, beginning of period	3,930	1,760
Cash and cash equivalents, end of period	4,281	2,982
Supplemental disclosures of cash flow information:
Interest paid	210	113
Income taxes paid	358	394
Equity issued in connection with acquisitions	$ 0	$ 3,105

Organization and Operations

Organization and Operations	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations	Organization and Operations Basis of Presentation The accompanying interim financial statements have been prepared under the presumption that users of the interim financial information have either read or have access to the audited financial statements included in the Form 10-K for the fiscal year ended December 31, 2016 . The unaudited interim financial statements herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, footnote disclosures which would substantially duplicate the disclosures contained in the December 31, 2016 audited financial statements have been omitted from these interim financial statements, where appropriate. In the opinion of management, these financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the results of the interim periods presented. Certain 2016 amounts in the consolidated financial statements and notes to the consolidated financial statements have been reclassified to conform to the 2017 presentation. The Company adopted Accounting Standards Update (ASU) 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The ASU simplifies several aspects of the accounting for employee share-based payment transactions. Among other elements, the ASU requires an entity to recognize all excess tax benefits and deficiencies related to stock-based compensation expense as income tax expense or benefit in the statements of operations. The ASU requires adjustments be reflected as of the beginning of the fiscal year of adoption and as a result, prior periods have been adjusted accordingly. The adoption resulted in a decrease to income tax expense of $2 million and $4 million for the three and nine months ended September 30, 2016 . In January 2017, the Company reclassified Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan from the Specialty Services segment to the Managed Care segment due to a reorganization of the Arizona management structure following the Health Net integration. As a result, the financial results of Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan have been reclassified from the Specialty Services segment to the Managed Care segment for all periods presented. On March 24, 2016 , the Company completed the acquisition of Health Net, Inc. (Health Net) for $6.0 billion , including the assumption of debt. The acquisition was accounted for as a business combination, which requires that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. The valuation of all the assets acquired and liabilities assumed was finalized in the fourth quarter of 2016. As a result of the completion of the Health Net acquisition, the Company's results of operations for the nine months ended September 30, 2016 include the results of operations of Health Net from March 24, 2016 to September 30, 2016 . Accounting Guidance Not Yet Adopted In August 2017, the Financial Accounting Standards Board (FASB) issued an ASU which amends the hedge accounting model to enable entities to better align the economics of risk management activities and financial reporting. In addition, the new standard enhances the understandability of hedge results and simplifies the application of hedge accounting in certain situations. The new guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The new guidance is not expected to have a material impact on the Company’s consolidated financial position, results of operations or cash flows. In March 2017, the FASB issued an ASU which changes the period over which premiums on callable debt securities are amortized. The new standard requires the premiums on callable debt securities to be amortized to the earliest call date rather than to the contractual maturity date of the instrument. The new guidance more closely aligns the amortization period of premiums to expectations incorporated in the market pricing on the underlying securities. The new guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The new guidance is not expected to have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2014, the FASB issued an ASU which supersedes existing revenue recognition standards with a single model, unless those contracts are within the scope of other standards (e.g., an insurance entity's insurance contracts). Under the new standard, recognition of revenue occurs when a customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenues and cash flows arising from contracts with customers. The guidance is effective for annual and interim periods beginning after December 15, 2017. Early adoption is permitted. The Company anticipates adopting the new guidance in the first quarter of 2018 using the modified retrospective approach with a cumulative-effect adjustment to retained earnings in the period of initial application. The Company also plans to elect the practical expedient of applying the new guidance only to contracts that are not completed as of the date of initial application. The majority of the Company's revenues are derived from insurance contracts and are excluded from the new standard. While the Company continues to analyze contracts within the scope of the standard, the new guidance is not expected to have a material impact on the Company's consolidated financial position, results of operations or cash flows.

Fidelis Care Transaction

Fidelis Care Transaction	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Fidelis Care Transaction	Fidelis Care Transaction In September 2017, the Company signed a definitive agreement under which Fidelis Care will become the Company's health plan in New York State. Under the terms of the agreement, the Company will acquire substantially all of the assets of Fidelis Care for $3.75 billion , subject to certain adjustments.

Acquisitions and Noncontrolling

Acquisitions and Noncontrolling Interest	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Acquisitions and Noncontrolling Interest	Acquisitions and Noncontrolling Interest In August 2017, the Company acquired the remaining 32% interest of U.S. Medical Management (USMM), a management services organization and provider of in-home health services for high acuity populations, for $86 million in total consideration. The transaction consideration consisted of $33 million of cash, $33 million of deferred consideration and $20 million related to the settlement of a receivable from the former noncontrolling interest holder. Redeemable Noncontrolling Interest As a result of put option agreements, noncontrolling interest is considered redeemable and is classified in the Redeemable Noncontrolling Interest section of the Consolidated Balance Sheets. A reconciliation of the changes in the Redeemable Noncontrolling Interest is as follows ($ in millions): Balance, December 31, 2016 $ 145 Noncontrolling interest purchased related to USMM (115 ) Contribution from redeemable noncontrolling interest 2 Net losses attributable to noncontrolling interests (12 ) Balance, September 30, 2017 $ 20

Short-term and Long-term Invest

Short-term and Long-term Investments, Restricted Deposits	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments, Restricted Deposits	Short-term and Long-term Investments, Restricted Deposits Short-term and long-term investments and restricted deposits by investment type consist of the following ($ in millions): September 30, 2017 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 330 $ — $ (1 ) $ 329 $ 364 $ — $ (1 ) $ 363 Corporate securities 2,098 18 (6 ) 2,110 1,933 12 (13 ) 1,932 Restricted certificates of deposit 4 — — 4 5 — — 5 Restricted cash equivalents 6 — — 6 6 — — 6 Municipal securities 1,979 16 (6 ) 1,989 1,767 1 (35 ) 1,733 Asset-backed securities 376 2 — 378 317 1 (1 ) 317 Residential mortgage-backed securities 309 1 (4 ) 306 219 1 (5 ) 215 Commercial mortgage-backed securities 238 1 (3 ) 236 343 — (5 ) 338 Cost and equity method investments 171 — — 171 163 — — 163 Life insurance contracts 131 — — 131 116 — — 116 Total $ 5,642 $ 38 $ (20 ) $ 5,660 $ 5,233 $ 15 $ (60 ) $ 5,188 The Company’s investments are classified as available-for-sale with the exception of life insurance contracts and certain cost and equity method investments. The Company’s investment policies are designed to provide liquidity, preserve capital and maximize total return on invested assets with the focus on high credit quality securities. The Company limits the size of investment in any single issuer other than U.S. treasury securities and obligations of U.S. government corporations and agencies. As of September 30, 2017 , 95% of the Company’s investments in rated securities carry an investment grade rating by nationally recognized statistical rating organizations. At September 30, 2017 , the Company held certificates of deposit, life insurance contracts and cost and equity method investments which did not carry a credit rating. The Company's residential mortgage-backed securities are primarily issued by the Federal National Mortgage Association, Government National Mortgage Association or Federal Home Loan Mortgage Corporation, which carry implicit or explicit guarantees of the U.S. government. The Company's commercial mortgage-backed securities are primarily senior tranches with a weighted average rating of AA+ and a weighted average duration of 4.1 years at September 30, 2017 . The fair value of available-for-sale investments with gross unrealized losses by investment type and length of time that individual securities have been in a continuous unrealized loss position were as follows ($ in millions): September 30, 2017 December 31, 2016 Less Than 12 Months 12 Months or More Less Than 12 Months 12 Months or More Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ (1 ) $ 277 $ — $ 3 $ (1 ) $ 215 $ — $ 2 Corporate securities (4 ) 587 (2 ) 83 (12 ) 1,020 (1 ) 39 Municipal securities (4 ) 457 (2 ) 96 (35 ) 1,423 — 30 Asset-backed securities — 126 — 13 (1 ) 101 — 18 Residential mortgage-backed securities (3 ) 190 (1 ) 49 (5 ) 188 — — Commercial mortgage-backed securities (1 ) 99 (2 ) 31 (5 ) 271 — — Total $ (13 ) $ 1,736 $ (7 ) $ 275 $ (59 ) $ 3,218 $ (1 ) $ 89 As of September 30, 2017 , the gross unrealized losses were generated from 1,201 positions out of a total of 3,192 positions. The change in fair value of fixed income securities is primarily a result of movement in interest rates subsequent to the purchase of the security. For each security in an unrealized loss position, the Company assesses whether it intends to sell the security or if it is more likely than not the Company will be required to sell the security before recovery of the amortized cost basis for reasons such as liquidity, contractual or regulatory purposes. If the security meets this criterion, the decline in fair value is other-than-temporary and is recorded in earnings. The Company does not intend to sell these securities prior to maturity and it is not likely that the Company will be required to sell these securities prior to maturity; therefore, there is no indication of other-than-temporary impairment for these securities. The contractual maturities of short-term and long-term investments and restricted deposits are as follows ($ in millions): September 30, 2017 December 31, 2016 Investments Restricted Deposits Investments Restricted Deposits Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 533 $ 533 $ 65 $ 65 $ 500 $ 500 $ 91 $ 91 One year through five years 2,149 2,162 73 73 1,982 1,974 47 47 Five years through ten years 1,680 1,687 — — 1,101 1,089 — — Greater than ten years 219 220 — — 633 617 — — Asset-backed securities 923 920 — — 879 870 — — Total $ 5,504 $ 5,522 $ 138 $ 138 $ 5,095 $ 5,050 $ 138 $ 138 Actual maturities may differ from contractual maturities due to call or prepayment options. Cost and equity method investments and life insurance contracts are included in the five years through ten years category. The Company has an option to redeem at amortized cost substantially all of the securities included in the greater than ten years category listed above. The Company continuously monitors investments for other-than-temporary impairment. Certain investments have experienced a decline in fair value due to changes in credit quality, market interest rates and/or general economic conditions. The Company recognizes an impairment loss for cost and equity method investments when evidence demonstrates that it is other-than-temporarily impaired. Evidence of a loss in value that is other-than-temporary may include the absence of an ability to recover the carrying amount of the investment or the inability of the investee to sustain a level of earnings that would justify the carrying amount of the investment.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Assets and liabilities recorded at fair value in the Consolidated Balance Sheets are categorized based upon observable or unobservable inputs used to estimate fair value. Level inputs are as follows: Level Input: Input Definition: Level I Inputs are unadjusted, quoted prices for identical assets or liabilities in active markets at the measurement date. Level II Inputs other than quoted prices included in Level I that are observable for the asset or liability through corroboration with market data at the measurement date. Level III Unobservable inputs that reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. The following table summarizes fair value measurements by level at September 30, 2017 , for assets and liabilities measured at fair value on a recurring basis ($ in millions): Level I Level II Level III Total Assets Cash and cash equivalents $ 4,281 $ — $ — $ 4,281 Investments available for sale: U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 201 $ — $ — $ 201 Corporate securities — 2,110 — 2,110 Municipal securities — 1,989 — 1,989 Asset-backed securities — 378 — 378 Residential mortgage-backed securities — 306 — 306 Commercial mortgage-backed securities — 236 — 236 Total investments $ 201 $ 5,019 $ — $ 5,220 Restricted deposits available for sale: Cash and cash equivalents $ 6 $ — $ — $ 6 Certificates of deposit 4 — — 4 U.S. Treasury securities and obligations of U.S. government corporations and agencies 128 — — 128 Total restricted deposits $ 138 $ — $ — $ 138 Other long-term assets: Interest rate swap agreements $ — $ 4 $ — $ 4 Total assets at fair value $ 4,620 $ 5,023 $ — $ 9,643 Liabilities Other long-term liabilities: Interest rate swap agreements $ — $ 53 $ — $ 53 Total liabilities at fair value $ — $ 53 $ — $ 53 The following table summarizes fair value measurements by level at December 31, 2016 , for assets and liabilities measured at fair value on a recurring basis ($ in millions): Level I Level II Level III Total Assets Cash and cash equivalents $ 3,930 $ — $ — $ 3,930 Investments available for sale: U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 221 $ 15 $ — $ 236 Corporate securities — 1,932 — 1,932 Municipal securities — 1,733 — 1,733 Asset-backed securities — 317 — 317 Residential mortgage-backed securities — 215 — 215 Commercial mortgage-backed securities — 338 — 338 Total investments $ 221 $ 4,550 $ — $ 4,771 Restricted deposits available for sale: Cash and cash equivalents $ 6 $ — $ — $ 6 Certificates of deposit 5 — — 5 U.S. Treasury securities and obligations of U.S. government corporations and agencies 127 — — 127 Total restricted deposits $ 138 $ — $ — $ 138 Other long-term assets: Interest rate swap agreements $ — $ 4 $ — $ 4 Total assets at fair value $ 4,289 $ 4,554 $ — $ 8,843 Liabilities Other long-term liabilities: Interest rate swap agreements $ — $ 62 $ — $ 62 Total liabilities at fair value $ — $ 62 $ — $ 62 The Company periodically transfers U.S. Treasury securities and obligations of U.S. government corporations and agencies between Level I and Level II fair value measurements dependent upon the level of trading activity for the specific securities at the measurement date. The Company’s policy regarding the timing of transfers between Level I and Level II is to measure and record the transfers at the end of the reporting period. At September 30, 2017 , there were no transfers from Level I to Level II and $14 million of transfers from Level II to Level I. The Company utilizes matrix pricing services to estimate fair value for securities which are not actively traded on the measurement date. The Company designates these securities as Level II fair value measurements. The aggregate carrying amount of the Company’s life insurance contracts and other non-majority owned investments, which approximates fair value, was $302 million and $279 million as of September 30, 2017 and December 31, 2016 , respectively.

Medical Claims Liability

Medical Claims Liability	9 Months Ended
	Sep. 30, 2017
Insurance [Abstract]
Medical Claims Liability	Medical Claims Liability In January 2017, the Company reclassified Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan from the Specialty Services segment to the Managed Care segment due to a reorganization of the Arizona management structure following the Health Net integration. As a result, the financial results of Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan have been reclassified from the Specialty Services segment to the Managed Care segment for all periods presented. Due to this change in segment reporting, the Specialty Services segment now has an insignificant amount of medical claims liability, and therefore disclosures related to medical claims liabilities have been aggregated and are presented on a consolidated basis. The following table summarizes the change in medical claims liability ($ in millions): Nine Months Ended September 30, 2017 2016 Balance, January 1 $ 3,929 $ 2,298 Less: Reinsurance Recoverable 5 — Balance, January 1, net 3,924 2,298 Acquisitions — 1,453 Incurred related to: Current year 28,666 22,372 Prior years (388 ) (300 ) Total incurred 28,278 22,072 Paid related to: Current year 24,787 20,121 Prior years 3,099 1,935 Total paid 27,886 22,056 Balance at September 30, net 4,316 3,767 Plus: Reinsurance Recoverable 17 — Balance, September 30 $ 4,333 $ 3,767 Reinsurance recoverables related to medical claims are included in premium and related receivables. Changes in estimates of incurred claims for prior years are primarily attributable to reserving under moderately adverse conditions. Additionally, as a result of development within "Incurred related to: Prior years" due to minimum HBR and other return of premium programs, we recorded approximately $4 million as an increase to premium revenues in the nine months ended September 30, 2017 and approximately $27 million as a reduction to premium revenues in the nine months ended September 30, 2016 . Incurred but not reported (IBNR) plus expected development on reported claims as of September 30, 2017 was $3,292 million . Total IBNR plus expected development on reported claims represents estimates for claims incurred but not reported, development on reported claims, and estimates for the costs necessary to process unpaid claims at the end of each period. We estimate our liability using actuarial methods that are commonly used by health insurance actuaries and meet Actuarial Standards of Practice. These actuarial methods consider factors such as historical data for payment patterns, cost trends, product mix, seasonality, utilization of healthcare services and other relevant factors.

Affordable Care Act

Affordable Care Act	9 Months Ended
	Sep. 30, 2017
Affordable Care Act [Abstract]
Affordable Care Act	Affordable Care Act The Affordable Care Act (ACA) established risk spreading premium stabilization programs effective January 1, 2014. These programs, commonly referred to as the “three Rs,” include a permanent risk adjustment program, a transitional reinsurance program, and a temporary risk corridor program. Additionally, the ACA established a minimum annual medical loss ratio (MLR) and cost sharing reductions. Each of the three R programs are taken into consideration to determine if the Company’s estimated annual medical costs are less than the minimum loss ratio and require an adjustment to Premium revenue to meet the minimum MLR. The 2016 benefit year was the final year for transitional reinsurance and risk corridor. No additional balances were recorded for the 2017 benefit year for these programs. During the second quarter of 2017, the Company recognized a $48 million net pre-tax benefit related to the reconciliation of the 2016 risk adjustment program compared to a $70 million net pre-tax benefit related to the reconciliation of the 2015 risk adjustment and reinsurance programs during the second quarter of 2016. The Company's net receivables (payables) for each of these programs are as follows ($ in millions): September 30, 2017 December 31, 2016 Risk adjustment $ (609 ) $ (425 ) Reinsurance 15 122 Risk corridor (8 ) (3 ) Minimum MLR (1 ) (18 ) Cost sharing reductions (180 ) (147 )

Debt

Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt	Debt Debt consists of the following ($ in millions): September 30, 2017 December 31, 2016 $1,400 million 5.625% Senior notes, due February 15, 2021 $ 1,400 $ 1,400 $1,000 million 4.75% Senior notes, due May 15, 2022 1,007 1,008 $1,000 million 6.125% Senior notes, due February 15, 2024 1,000 1,000 $1,200 million 4.75% Senior notes, due January 15, 2025 1,200 1,200 Fair value of interest rate swap agreements (49 ) (58 ) Total senior notes 4,558 4,550 Revolving credit agreement 150 100 Mortgage notes payable 62 64 Capital leases and other 17 18 Debt issuance costs (66 ) (77 ) Total debt 4,721 4,655 Less current portion (4 ) (4 ) Long-term debt $ 4,717 $ 4,651 Senior Notes The indentures governing the senior notes listed in the table above, contain non-financial and financial covenants of Centene Corporation, including requirements of a minimum fixed charge coverage ratio. At September 30, 2017 , the Company was in compliance with all covenants. Interest Rate Swaps In February 2017 and in connection with the November 2016 issuance of $1,200 million of 4.75% Senior Notes, due January 15, 2025 ( $1,200 Million Notes), the Company entered into interest rate swap agreements for a notional amount of $600 million , at floating rates of interest based on the one month LIBOR plus 2.53% . Gains and losses due to the changes in the fair value of the interest rate swaps completely offset changes in the fair value of the hedged portion of the underlying debt and are recorded as an adjustment to the $1,200 Million Notes. The Company uses interest rate swap agreements to convert a portion of its interest rate exposure from fixed rates to floating rates to more closely align interest expense with interest income received on its cash equivalent and variable rate investment balances. The Company has $2,700 million of notional amount of interest rate swap agreements consisting of: • $600 million expiring on February 15, 2021; • $500 million expiring on May 15, 2022 ; • $1,000 million expiring on February 15, 2024; and • $600 million expiring on January 15, 2025. Under the swap agreements, the Company receives a fixed rate of interest and pays an average variable rate of either the three or one month LIBOR plus 3.61% adjusted monthly or quarterly, based on the terms of the individual swap agreements. At September 30, 2017 , the weighted average rate was 4.91% . The swap agreements are formally designated and qualify as fair value hedges and are recorded at fair value in the Consolidated Balance Sheets in other assets or other liabilities. Gains and losses due to changes in fair value of the interest rate swap agreements completely offset changes in the fair value of the hedged portion of the underlying debt. Therefore, no gain or loss has been recognized due to hedge ineffectiveness. Offsetting changes in fair value of both the interest rate swaps and the hedged portion of the underlying debt both were recognized in interest expense in the Consolidated Statements of Operations. The Company does not hold or issue any derivative instrument for trading or speculative purposes. Revolving Credit Agreement The Company has an unsecured $1,000 million revolving credit facility. Borrowings under the agreement bear interest based upon LIBOR rates, the Federal Funds Rate or the Prime Rate. The agreement has a maturity date of March 24, 2021 . As of September 30, 2017 , the Company had $150 million of borrowings outstanding under the agreement with a weighted average interest rate of 4.75% . The revolving credit facility contains non-financial and financial covenants, including requirements of minimum fixed charge coverage ratios and maximum debt-to-EBITDA ratios. The Company is required to not exceed a maximum debt-to-EBITDA ratio of 3.0 to 1.0 on and subsequent to December 31, 2016. As of September 30, 2017 , there were no limitations on the availability under the revolving credit agreement as a result of the debt-to-EBITDA ratio, and the Company was in compliance with all covenants. Letters of Credit & Surety Bonds The Company had outstanding letters of credit of $51 million as of September 30, 2017 , which were not part of the revolving credit facility. The Company also had letters of credit for $45 million (valued at September 30, 2017 conversion rate), or €38 million , representing its proportional share of the letters of credit issued to support Ribera Salud’s outstanding debt, which are a part of the revolving credit facility. Collectively, the letters of credit bore interest at 1.33% as of September 30, 2017 . The Company had outstanding surety bonds of $404 million as of September 30, 2017 . Construction Loan In October 2017, the Company executed a $200 million non-recourse construction loan to fund the expansion of the Company's corporate headquarters. The loan bears interest based on the one month LIBOR plus 2.70% and matures in April 2021 with an optional one-year extension. The agreement contains financial and non-financial covenants aligning with the Company's revolving credit agreement . The Company has guaranteed completion of the construction project associated with the loan.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the calculation of basic and diluted net earnings (loss) per common share ($ in millions, except shares in thousands and per share data in dollars): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Earnings attributable to Centene Corporation: Earnings from continuing operations, net of tax $ 205 $ 148 $ 598 $ 304 Discontinued operations, net of tax — (1 ) — (3 ) Net earnings $ 205 $ 147 $ 598 $ 301 Shares used in computing per share amounts: Weighted average number of common shares outstanding 172,508 170,775 172,314 155,681 Common stock equivalents (as determined by applying the treasury stock method) 4,407 4,720 4,100 4,376 Weighted average number of common shares and potential dilutive common shares outstanding 176,915 175,495 176,414 160,057 Net earnings (loss) per common share attributable to Centene Corporation: Basic: Continuing operations $ 1.19 $ 0.87 $ 3.47 $ 1.95 Discontinued operations — (0.01 ) — (0.02 ) Basic earnings per common share $ 1.19 $ 0.86 $ 3.47 $ 1.93 Diluted: Continuing operations $ 1.16 $ 0.84 $ 3.39 $ 1.90 Discontinued operations — — — (0.02 ) Diluted earnings per common share $ 1.16 $ 0.84 $ 3.39 $ 1.88 The calculation of diluted earnings per common share for the three and nine months ended September 30, 2017 excludes the impact of 4 thousand and 27 thousand shares, respectively, related to anti-dilutive stock options, restricted stock and restricted stock units. The calculation of diluted earnings per common share for the three and nine months ended September 30, 2016 excludes the impact of 57 thousand and 66 thousand shares, respectively, related to anti-dilutive stock options, restricted stock and restricted stock units.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information Centene operates in two segments: Managed Care and Specialty Services. The Managed Care segment consists of Centene’s health plans including all of the functions needed to operate them. The Specialty Services segment consists of Centene’s specialty companies offering auxiliary healthcare services and products. In January 2017, the Company reclassified Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan from the Specialty Services segment to the Managed Care segment due to a reorganization of the Arizona management structure following the Health Net integration. As a result, the financial results of Cenpatico Behavioral Health of Arizona, LLC and the related Cenpatico Integrated Care health plan have been reclassified from the Specialty Services segment to the Managed Care segment for all periods presented. Segment information for the three months ended September 30, 2017 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 11,248 $ 650 $ — $ 11,898 Total revenues from internal customers 11 2,367 (2,378 ) — Total revenues $ 11,259 $ 3,017 $ (2,378 ) $ 11,898 Earnings from operations $ 238 $ 102 $ — $ 340 Segment information for the three months ended September 30, 2016 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 10,175 $ 671 $ — $ 10,846 Total revenues from internal customers 56 1,524 (1,580 ) — Total revenues $ 10,231 $ 2,195 $ (1,580 ) $ 10,846 Earnings from operations $ 309 $ 33 $ — $ 342 Segment information for the nine months ended September 30, 2017 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 33,704 $ 1,872 $ — $ 35,576 Total revenues from internal customers 33 7,112 (7,145 ) — Total revenues $ 33,737 $ 8,984 $ (7,145 ) $ 35,576 Earnings from operations $ 799 $ 219 $ — $ 1,018 Segment information for the nine months ended September 30, 2016 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 26,926 $ 1,770 $ — $ 28,696 Total revenues from internal customers 144 4,383 (4,527 ) — Total revenues $ 27,070 $ 6,153 $ (4,527 ) $ 28,696 Earnings from operations $ 627 $ 112 $ — $ 739

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Overview The Company records reserves and accrues costs for certain legal proceedings and regulatory matters to the extent that it determines an unfavorable outcome is probable and the amount of the loss can be reasonably estimated. While such reserves and accrued costs reflect the Company's best estimate of the probable loss for such matters, the recorded amounts may differ materially from the actual amount of any such losses. In some cases, no estimate of the possible loss or range of loss in excess of amounts accrued, if any, can be made because of the inherently unpredictable nature of legal and regulatory proceedings, which may be exacerbated by various factors, including but not limited to, they may involve indeterminate claims for monetary damages or may involve fines, penalties or punitive damages; present novel legal theories or legal uncertainties; involve disputed facts; represent a shift in regulatory policy; involve a large number of parties, claimants or regulatory bodies; are in the early stages of the proceedings; involve a number of separate proceedings and/or a wide range of potential outcomes; or result in a change of business practices. As of the date of this report, amounts accrued for legal proceedings and regulatory matters were not material. However, it is possible that in a particular quarter or annual period the Company’s financial condition, results of operations, cash flow and/or liquidity could be materially adversely affected by an ultimate unfavorable resolution of or development in legal and/or regulatory proceedings, including as described below. Except for the proceedings discussed below, the Company believes that the ultimate outcome of any of the regulatory and legal proceedings that are currently pending against it should not have a material adverse effect on financial condition, results of operations, cash flow or liquidity. California The Company's California subsidiary, Health Net of California, Inc. (Health Net California), has been named as a defendant in a California taxpayer action filed in Los Angeles County Superior Court, captioned as Michael D. Myers v. State Board of Equalization, et al., Los Angeles Superior Court Case No. BS158655. This action is brought under a California statute that permits an individual taxpayer to sue a governmental agency when the taxpayer believes the agency has failed to enforce governing law. Plaintiff contends that Health Net California, a California licensed Health Care Service Plan (HCSP), is an “insurer” for purposes of taxation despite acknowledging it is not an “insurer” under regulatory law. Under California law, “insurers” must pay a gross premiums tax (GPT), calculated as 2.35% on gross premiums. As a licensed HCSP, Health Net California has paid the California Corporate Franchise Tax (CFT), the tax generally paid by California businesses. Plaintiff contends that Health Net California must pay the GPT rather than the CFT. Plaintiff seeks a writ of mandate directing the California taxing agencies to collect the GPT, and seeks an order requiring Health Net California to pay GPT, interest and penalties for a period dating to eight years prior to the October 2015 filing of the complaint. This lawsuit is being coordinated with similar lawsuits filed against other entities. An initial status conference was held in June 2017 wherein the Court set a schedule for challenges to the pleadings. In September 2017, the Company filed a demurrer seeking to dismiss the complaint, and a motion to strike the allegations seeking retroactive relief. The Company intends to vigorously defend itself against these claims; however, this matter is subject to many uncertainties, and an adverse outcome in this matter could potentially have a materially adverse impact on our financial position, results of operations and cash flows. Federal Securities Class Action In November 2016, a putative federal securities class action was filed against the Company and certain of its executives in the U.S. District Court for the Central District of California. In March 2017, the court entered an order transferring the matter to the U.S. District Court for the Eastern District of Missouri. The plaintiffs in the lawsuit allege that the Company's accounting and related disclosures for certain liabilities acquired in the acquisition of Health Net violated federal securities laws. In July 2017, the lead plaintiff filed a Consolidated Class Action Complaint. The Company filed a motion to dismiss this complaint in September 2017. The Company denies any wrongdoing and is vigorously defending itself against these claims. Nevertheless, this matter is subject to many uncertainties and the Company cannot predict how long this litigation will last or what the ultimate outcome will be, and an adverse outcome in this matter could potentially have a materially adverse impact on our financial position and results of operations. Medicare Parts C and D Matter In December 2016, a Civil Investigative Demand (CID) was issued to Health Net by the United States Department of Justice regarding Health Net’s submission of risk adjustment claims to CMS under Parts C and D of Medicare. The CID may be related to a federal qui tam lawsuit filed under seal in 2011 naming more than a dozen health insurers including Health Net. The lawsuit was unsealed in February 2017 when the Department of Justice intervened in the case with respect to one of the insurers (not Health Net). The Company is complying with the CID and will vigorously defend any lawsuits. At this point, it is not possible to determine what level of liability, if any, the Company may face as a result of this matter. Veterans Administrative Matter In October 2017, a CID was issued to Health Net Federal Services, LLC (HNFS) by the United States Department of Justice. The CID seeks documents and interrogatory responses concerning whether HNFS submitted, or caused to be submitted, excessive, duplicative or otherwise improper claims to the U.S. Department of Veterans Affairs under a contract to arrange health care services for veterans. The contract began in late 2014. In 2016, modifications to the contract were made to allow for possible duplicate billings with a reconciliation period at the end of the contract term. The Company is complying with the CID and believes it has been meeting its contractual obligations. At this point, it is not possible to determine what level of liability, if any, the Company may face as a result of this matter. Guaranty Fund Assessment Under state guaranty association laws, certain insurance companies can be assessed for certain obligations to the policyholders and claimants of impaired or insolvent insurance companies that write the same line or similar lines of business. In 2009, the Pennsylvania Insurance Commissioner placed long-term care insurer Penn Treaty Network America Insurance Company and its subsidiary (Penn Treaty), neither of which is affiliated with the Company, in rehabilitation and petitioned a state court for approval to liquidate Penn Treaty. In March 2017, the court issued the final liquidation order, and as a result, during the nine months ended September 30, 2017 , the Company recognized $56 million representing its undiscounted estimated share of the guaranty association assessment as selling, general and administrative expenses. Miscellaneous Proceedings Excluding the matters discussed above, the Company is also routinely subjected to legal and regulatory proceedings in the normal course of business. These matters can include, without limitation: • periodic compliance and other reviews and investigations by various federal and state regulatory agencies with respect to requirements applicable to the Company's business, including, without limitation, those related to payment of out-of-network claims, submissions to CMS for risk adjustment payments or the False Claims Act, pre-authorization penalties, timely review of grievances and appeals, timely and accurate payment of claims, and the Health Insurance Portability and Accountability Act of 1996; • litigation arising out of general business activities, such as tax matters, disputes related to health care benefits coverage or reimbursement, putative securities class actions and medical malpractice, privacy, real estate, intellectual property and employment-related claims; • disputes regarding reinsurance arrangements, claims arising out of the acquisition or divestiture of various assets, class actions and claims relating to the performance of contractual and non-contractual obligations to providers, members, employer groups and others, including, but not limited to, the alleged failure to properly pay claims and challenges to the manner in which the Company processes claims, and claims alleging that the Company has engaged in unfair business practices. Among other things, these matters may result in awards of damages, fines or penalties, which could be substantial, and/or could require changes to the Company’s business. The Company intends to vigorously defend itself against the miscellaneous legal and regulatory proceedings to which it is currently a party; however, these proceedings are subject to many uncertainties. In some of the cases pending against the Company, substantial non-economic or punitive damages are being sought.

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On October 1, 2017, the Company acquired 80% of a national, full-service specialty pharmacy, providing service to patients with certain chronic respiratory and digestive conditions. The purchase price consists of $53 million in cash paid at closing, $7 million in deferred consideration, and up to an additional $32 million of contingent consideration to be paid upon meeting certain performance metrics.

Acquisitions and Noncontrolli21

Acquisitions and Noncontrolling Interest (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Reconciliation of Changes in Redeemable Noncontrolling Interest	A reconciliation of the changes in the Redeemable Noncontrolling Interest is as follows ($ in millions): Balance, December 31, 2016 $ 145 Noncontrolling interest purchased related to USMM (115 ) Contribution from redeemable noncontrolling interest 2 Net losses attributable to noncontrolling interests (12 ) Balance, September 30, 2017 $ 20

Short-term and Long-term Inve22

Short-term and Long-term Investments, Restricted Deposits (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Short-term and long-term investments and restricted deposits by investment type	Short-term and long-term investments and restricted deposits by investment type consist of the following ($ in millions): September 30, 2017 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 330 $ — $ (1 ) $ 329 $ 364 $ — $ (1 ) $ 363 Corporate securities 2,098 18 (6 ) 2,110 1,933 12 (13 ) 1,932 Restricted certificates of deposit 4 — — 4 5 — — 5 Restricted cash equivalents 6 — — 6 6 — — 6 Municipal securities 1,979 16 (6 ) 1,989 1,767 1 (35 ) 1,733 Asset-backed securities 376 2 — 378 317 1 (1 ) 317 Residential mortgage-backed securities 309 1 (4 ) 306 219 1 (5 ) 215 Commercial mortgage-backed securities 238 1 (3 ) 236 343 — (5 ) 338 Cost and equity method investments 171 — — 171 163 — — 163 Life insurance contracts 131 — — 131 116 — — 116 Total $ 5,642 $ 38 $ (20 ) $ 5,660 $ 5,233 $ 15 $ (60 ) $ 5,188
Fair value of available-for-sale investments with gross unrealized losses byinvestment type and length of time	The fair value of available-for-sale investments with gross unrealized losses by investment type and length of time that individual securities have been in a continuous unrealized loss position were as follows ($ in millions): September 30, 2017 December 31, 2016 Less Than 12 Months 12 Months or More Less Than 12 Months 12 Months or More Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ (1 ) $ 277 $ — $ 3 $ (1 ) $ 215 $ — $ 2 Corporate securities (4 ) 587 (2 ) 83 (12 ) 1,020 (1 ) 39 Municipal securities (4 ) 457 (2 ) 96 (35 ) 1,423 — 30 Asset-backed securities — 126 — 13 (1 ) 101 — 18 Residential mortgage-backed securities (3 ) 190 (1 ) 49 (5 ) 188 — — Commercial mortgage-backed securities (1 ) 99 (2 ) 31 (5 ) 271 — — Total $ (13 ) $ 1,736 $ (7 ) $ 275 $ (59 ) $ 3,218 $ (1 ) $ 89
Contractual maturities of short-term and long-term investments and restricted deposits	The contractual maturities of short-term and long-term investments and restricted deposits are as follows ($ in millions): September 30, 2017 December 31, 2016 Investments Restricted Deposits Investments Restricted Deposits Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 533 $ 533 $ 65 $ 65 $ 500 $ 500 $ 91 $ 91 One year through five years 2,149 2,162 73 73 1,982 1,974 47 47 Five years through ten years 1,680 1,687 — — 1,101 1,089 — — Greater than ten years 219 220 — — 633 617 — — Asset-backed securities 923 920 — — 879 870 — — Total $ 5,504 $ 5,522 $ 138 $ 138 $ 5,095 $ 5,050 $ 138 $ 138

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements by Level for Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table summarizes fair value measurements by level at September 30, 2017 , for assets and liabilities measured at fair value on a recurring basis ($ in millions): Level I Level II Level III Total Assets Cash and cash equivalents $ 4,281 $ — $ — $ 4,281 Investments available for sale: U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 201 $ — $ — $ 201 Corporate securities — 2,110 — 2,110 Municipal securities — 1,989 — 1,989 Asset-backed securities — 378 — 378 Residential mortgage-backed securities — 306 — 306 Commercial mortgage-backed securities — 236 — 236 Total investments $ 201 $ 5,019 $ — $ 5,220 Restricted deposits available for sale: Cash and cash equivalents $ 6 $ — $ — $ 6 Certificates of deposit 4 — — 4 U.S. Treasury securities and obligations of U.S. government corporations and agencies 128 — — 128 Total restricted deposits $ 138 $ — $ — $ 138 Other long-term assets: Interest rate swap agreements $ — $ 4 $ — $ 4 Total assets at fair value $ 4,620 $ 5,023 $ — $ 9,643 Liabilities Other long-term liabilities: Interest rate swap agreements $ — $ 53 $ — $ 53 Total liabilities at fair value $ — $ 53 $ — $ 53 The following table summarizes fair value measurements by level at December 31, 2016 , for assets and liabilities measured at fair value on a recurring basis ($ in millions): Level I Level II Level III Total Assets Cash and cash equivalents $ 3,930 $ — $ — $ 3,930 Investments available for sale: U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 221 $ 15 $ — $ 236 Corporate securities — 1,932 — 1,932 Municipal securities — 1,733 — 1,733 Asset-backed securities — 317 — 317 Residential mortgage-backed securities — 215 — 215 Commercial mortgage-backed securities — 338 — 338 Total investments $ 221 $ 4,550 $ — $ 4,771 Restricted deposits available for sale: Cash and cash equivalents $ 6 $ — $ — $ 6 Certificates of deposit 5 — — 5 U.S. Treasury securities and obligations of U.S. government corporations and agencies 127 — — 127 Total restricted deposits $ 138 $ — $ — $ 138 Other long-term assets: Interest rate swap agreements $ — $ 4 $ — $ 4 Total assets at fair value $ 4,289 $ 4,554 $ — $ 8,843 Liabilities Other long-term liabilities: Interest rate swap agreements $ — $ 62 $ — $ 62 Total liabilities at fair value $ — $ 62 $ — $ 62

Medical Claims Liability (Table

Medical Claims Liability (Tables)	9 Months Ended
	Sep. 30, 2017
Insurance [Abstract]
Schedule of change in medical claims liability	The following table summarizes the change in medical claims liability ($ in millions): Nine Months Ended September 30, 2017 2016 Balance, January 1 $ 3,929 $ 2,298 Less: Reinsurance Recoverable 5 — Balance, January 1, net 3,924 2,298 Acquisitions — 1,453 Incurred related to: Current year 28,666 22,372 Prior years (388 ) (300 ) Total incurred 28,278 22,072 Paid related to: Current year 24,787 20,121 Prior years 3,099 1,935 Total paid 27,886 22,056 Balance at September 30, net 4,316 3,767 Plus: Reinsurance Recoverable 17 — Balance, September 30 $ 4,333 $ 3,767

Affordable Care Act (Tables)

Affordable Care Act (Tables)	9 Months Ended
	Sep. 30, 2017
Affordable Care Act [Abstract]
Schedule of Receivables (Payables) Related to the Affordable Care Act Programs	The Company's net receivables (payables) for each of these programs are as follows ($ in millions): September 30, 2017 December 31, 2016 Risk adjustment $ (609 ) $ (425 ) Reinsurance 15 122 Risk corridor (8 ) (3 ) Minimum MLR (1 ) (18 ) Cost sharing reductions (180 ) (147 )

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Debt	Debt consists of the following ($ in millions): September 30, 2017 December 31, 2016 $1,400 million 5.625% Senior notes, due February 15, 2021 $ 1,400 $ 1,400 $1,000 million 4.75% Senior notes, due May 15, 2022 1,007 1,008 $1,000 million 6.125% Senior notes, due February 15, 2024 1,000 1,000 $1,200 million 4.75% Senior notes, due January 15, 2025 1,200 1,200 Fair value of interest rate swap agreements (49 ) (58 ) Total senior notes 4,558 4,550 Revolving credit agreement 150 100 Mortgage notes payable 62 64 Capital leases and other 17 18 Debt issuance costs (66 ) (77 ) Total debt 4,721 4,655 Less current portion (4 ) (4 ) Long-term debt $ 4,717 $ 4,651

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Net Earnings (Loss) Per Common Share	The following table sets forth the calculation of basic and diluted net earnings (loss) per common share ($ in millions, except shares in thousands and per share data in dollars): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Earnings attributable to Centene Corporation: Earnings from continuing operations, net of tax $ 205 $ 148 $ 598 $ 304 Discontinued operations, net of tax — (1 ) — (3 ) Net earnings $ 205 $ 147 $ 598 $ 301 Shares used in computing per share amounts: Weighted average number of common shares outstanding 172,508 170,775 172,314 155,681 Common stock equivalents (as determined by applying the treasury stock method) 4,407 4,720 4,100 4,376 Weighted average number of common shares and potential dilutive common shares outstanding 176,915 175,495 176,414 160,057 Net earnings (loss) per common share attributable to Centene Corporation: Basic: Continuing operations $ 1.19 $ 0.87 $ 3.47 $ 1.95 Discontinued operations — (0.01 ) — (0.02 ) Basic earnings per common share $ 1.19 $ 0.86 $ 3.47 $ 1.93 Diluted: Continuing operations $ 1.16 $ 0.84 $ 3.39 $ 1.90 Discontinued operations — — — (0.02 ) Diluted earnings per common share $ 1.16 $ 0.84 $ 3.39 $ 1.88

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment information for the three months ended September 30, 2017 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 11,248 $ 650 $ — $ 11,898 Total revenues from internal customers 11 2,367 (2,378 ) — Total revenues $ 11,259 $ 3,017 $ (2,378 ) $ 11,898 Earnings from operations $ 238 $ 102 $ — $ 340 Segment information for the three months ended September 30, 2016 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 10,175 $ 671 $ — $ 10,846 Total revenues from internal customers 56 1,524 (1,580 ) — Total revenues $ 10,231 $ 2,195 $ (1,580 ) $ 10,846 Earnings from operations $ 309 $ 33 $ — $ 342 Segment information for the nine months ended September 30, 2017 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 33,704 $ 1,872 $ — $ 35,576 Total revenues from internal customers 33 7,112 (7,145 ) — Total revenues $ 33,737 $ 8,984 $ (7,145 ) $ 35,576 Earnings from operations $ 799 $ 219 $ — $ 1,018 Segment information for the nine months ended September 30, 2016 , follows ($ in millions): Managed Care Specialty Services Eliminations Consolidated Total Total revenues from external customers $ 26,926 $ 1,770 $ — $ 28,696 Total revenues from internal customers 144 4,383 (4,527 ) — Total revenues $ 27,070 $ 6,153 $ (4,527 ) $ 28,696 Earnings from operations $ 627 $ 112 $ — $ 739

Organization and Operations (De

Organization and Operations (Details) - USD ($) $ in Millions	Mar. 24, 2016	Sep. 30, 2016	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Decrease to income tax expense due to adoption of ASU 2016-09		$ 2	$ 4
Health Net, Inc.
Business Acquisition [Line Items]
Business combination, consideration transferred, including assumed debt	$ 6,000

Fidelis Care Transaction (Detai

Fidelis Care Transaction (Details) $ in Millions	Sep. 30, 2017USD ($)
Fidelis Care
Business Acquisition [Line Items]
Definitive agreement to acquire amount	$ 3,750

Acquisitions and Noncontrolli31

Acquisitions and Noncontrolling Interest - Narrative (Details) - U.S. Medical Management $ in Millions	1 Months Ended
	Aug. 31, 2017USD ($)
Business Acquisition [Line Items]
Percentage of ownership interests acquired	32.00%
Consideration transferred	$ 86
Cash paid to acquire business	33
Deferred consideration	33
Settlement of receivable from former noncontrolling interest holder	$ 20

Acquisitions and Noncontrolli32

Acquisitions and Noncontrolling Interest - Reconciliation of Changes in Redeemable Noncontrolling Interest (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance, December 31, 2016	$ 145
Noncontrolling interest purchased related to USMM	(115)
Contribution from redeemable noncontrolling interest	2
Net losses attributable to noncontrolling interests	(12)
Balance, September 30, 2017	$ 20

Short-term and Long-term Inve33

Short-term and Long-term Investments, Restricted Deposits (By Investment Type) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	$ 5,642	$ 5,233
Gross Unrealized Gains	38	15
Gross Unrealized Losses	(20)	(60)
Fair Value	5,660	5,188
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	330	364
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	329	363
Corporate securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	2,098	1,933
Gross Unrealized Gains	18	12
Gross Unrealized Losses	(6)	(13)
Fair Value	2,110	1,932
Restricted certificates of deposit
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	4	5
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	4	5
Restricted cash equivalents
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	6	6
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	6	6
Municipal securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	1,979	1,767
Gross Unrealized Gains	16	1
Gross Unrealized Losses	(6)	(35)
Fair Value	1,989	1,733
Asset-backed securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	376	317
Gross Unrealized Gains	2	1
Gross Unrealized Losses	0	(1)
Fair Value	378	317
Residential mortgage-backed securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	309	219
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(4)	(5)
Fair Value	306	215
Commercial mortgage-backed securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	238	343
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(3)	(5)
Fair Value	236	338
Cost and equity method investments
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	171	163
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	171	163
Life insurance contracts
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	131	116
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 131	$ 116

Short-term and Long-term Inve34

Short-term and Long-term Investments, Restricted Deposits (Narrative) (Details)	9 Months Ended
	Sep. 30, 2017position
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Positions from which gross unrealized losses were generated	1,201
Total unrealized investment positions	3,192
Commercial mortgage-backed securities
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Investments recorded at fair value that carry rating of AA Plus, weighted average (in years)	4 years 1 month 6 days
Rated Securities | External Credit Rating, Investment Grade
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Percentage of investments in rated securities carry an investment grade rating by nationally recognized statistical rating organizations	95.00%

Short-term and Long-term Inve35

Short-term and Long-term Investments, Restricted Deposits (Fair Value of Available-For-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Unrealized Losses
Less Than 12 Months	$ (13)	$ (59)
12 Months or More	(7)	(1)
Fair Value
Less Than 12 Months	1,736	3,218
12 Months or More	275	89
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Unrealized Losses
Less Than 12 Months	(1)	(1)
12 Months or More	0	0
Fair Value
Less Than 12 Months	277	215
12 Months or More	3	2
Corporate securities
Unrealized Losses
Less Than 12 Months	(4)	(12)
12 Months or More	(2)	(1)
Fair Value
Less Than 12 Months	587	1,020
12 Months or More	83	39
Municipal securities
Unrealized Losses
Less Than 12 Months	(4)	(35)
12 Months or More	(2)	0
Fair Value
Less Than 12 Months	457	1,423
12 Months or More	96	30
Asset-backed securities
Unrealized Losses
Less Than 12 Months	0	(1)
12 Months or More	0	0
Fair Value
Less Than 12 Months	126	101
12 Months or More	13	18
Residential mortgage-backed securities
Unrealized Losses
Less Than 12 Months	(3)	(5)
12 Months or More	(1)	0
Fair Value
Less Than 12 Months	190	188
12 Months or More	49	0
Commercial mortgage-backed securities
Unrealized Losses
Less Than 12 Months	(1)	(5)
12 Months or More	(2)	0
Fair Value
Less Than 12 Months	99	271
12 Months or More	$ 31	$ 0

Short-term and Long-term Inve36

Short-term and Long-term Investments, Restricted Deposits (Contractual Maturities of Short-Term and Long-Term Investments and Restricted Deposits) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost, one year or less	$ 533	$ 500
Amortized cost, one year through five years	2,149	1,982
Amortized cost, five years through ten years	1,680	1,101
Amortized cost, greater than ten years	219	633
Amortized cost, asset-backed securities	923	879
Amortized cost, total	5,504	5,095
Fair value, one year or less	533	500
Fair value, one year through five years	2,162	1,974
Fair value, five years through ten years	1,687	1,089
Fair value, greater than ten years	220	617
Fair value, asset-backed securities	920	870
Fair value, total	5,522	5,050
Restricted Deposits
Schedule of Available-for-sale Securities [Line Items]
Amortized cost, one year or less	65	91
Amortized cost, one year through five years	73	47
Amortized cost, five years through ten years	0	0
Amortized cost, greater than ten years	0	0
Amortized cost, asset-backed securities	0	0
Amortized cost, total	138	138
Fair value, one year or less	65	91
Fair value, one year through five years	73	47
Fair value, five years through ten years	0	0
Fair value, greater than ten years	0	0
Fair value, asset-backed securities	0	0
Fair value, total	$ 138	$ 138

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurements by Level for Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 4,281	$ 3,930
U.S. Treasury securities and obligations of U.S. government corporations and agencies	201	236
Corporate securities	2,110	1,932
Municipal securities	1,989	1,733
Asset-backed securities	378	317
Total investments	5,220	4,771
Cash and cash equivalents	6	6
Certificates of deposit	4	5
U.S. Treasury securities and obligations of U.S. government corporations and agencies	128	127
Total restricted deposits	138	138
Interest rate swap agreements	4	4
Total assets at fair value	9,643	8,843
Liabilities
Interest rate swap agreements	53	62
Total liabilities at fair value	53	62
Residential mortgage-backed securities
Assets
Mortgage-backed securities	306	215
Commercial mortgage-backed securities
Assets
Mortgage-backed securities	236	338
Level I
Assets
Cash and cash equivalents	4,281	3,930
U.S. Treasury securities and obligations of U.S. government corporations and agencies	201	221
Corporate securities	0	0
Municipal securities	0	0
Asset-backed securities	0	0
Total investments	201	221
Cash and cash equivalents	6	6
Certificates of deposit	4	5
U.S. Treasury securities and obligations of U.S. government corporations and agencies	128	127
Total restricted deposits	138	138
Interest rate swap agreements	0	0
Total assets at fair value	4,620	4,289
Liabilities
Interest rate swap agreements	0	0
Total liabilities at fair value	0	0
Level I | Residential mortgage-backed securities
Assets
Mortgage-backed securities	0	0
Level I | Commercial mortgage-backed securities
Assets
Mortgage-backed securities	0	0
Level II
Assets
Cash and cash equivalents	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies	0	15
Corporate securities	2,110	1,932
Municipal securities	1,989	1,733
Asset-backed securities	378	317
Total investments	5,019	4,550
Cash and cash equivalents	0	0
Certificates of deposit	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies	0	0
Total restricted deposits	0	0
Interest rate swap agreements	4	4
Total assets at fair value	5,023	4,554
Liabilities
Interest rate swap agreements	53	62
Total liabilities at fair value	53	62
Level II | Residential mortgage-backed securities
Assets
Mortgage-backed securities	306	215
Level II | Commercial mortgage-backed securities
Assets
Mortgage-backed securities	236	338
Level III
Assets
Cash and cash equivalents	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies	0	0
Corporate securities	0	0
Municipal securities	0	0
Asset-backed securities	0	0
Total investments	0	0
Cash and cash equivalents	0	0
Certificates of deposit	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies	0	0
Total restricted deposits	0	0
Interest rate swap agreements	0	0
Total assets at fair value	0	0
Liabilities
Interest rate swap agreements	0	0
Total liabilities at fair value	0	0
Level III | Residential mortgage-backed securities
Assets
Mortgage-backed securities	0	0
Level III | Commercial mortgage-backed securities
Assets
Mortgage-backed securities	$ 0	$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Transfers from Level I to Level II	$ 0
Transfers from Level II to Level I	14,000,000
Life insurance contracts and other non-majority owned investments, fair value	$ 302,000,000	$ 279,000,000

Medical Claims Liability (Sched

Medical Claims Liability (Schedule of Change in Medical Claims Liability) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, January 1	$ 3,929	$ 2,298
Less: Reinsurance Recoverable	5	0
Balance, January 1, net	3,924	2,298
Acquisitions	0	1,453
Incurred related to:
Current year	28,666	22,372
Prior years	(388)	(300)
Total incurred	28,278	22,072
Paid related to:
Current year	24,787	20,121
Prior years	3,099	1,935
Total paid	27,886	22,056
Balance at September 30, net	4,316	3,767
Plus: Reinsurance Recoverable	17	0
Balance, September 30	$ 4,333	$ 3,767

Medical Claims Liability (Narra

Medical Claims Liability (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Insurance [Abstract]
Amounts recorded as an adjustment to premium revenues related to minimum HBR and return of premium programs	$ (4)	$ 27
Short-duration insurance contracts, Incurred but not reported and expected development on reported claims	$ 3,292

Affordable Care Act (Details)

Affordable Care Act (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Affordable Care Act [Abstract]
Risk adjustment and reinsurance, pre-tax benefit, period increase (decrease)	$ 48	$ 70
Risk adjustment			$ (609)	$ (425)
Reinsurance			15	122
Risk corridor			(8)	(3)
Minimum MLR			(1)	(18)
Cost sharing reductions			$ (180)	$ (147)

Debt - (Schedule of Debt) (Deta

Debt - (Schedule of Debt) (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016	Nov. 30, 2016
Debt Instrument [Line Items]
Fair value of interest rate swap agreements	$ (49,000,000)	$ (58,000,000)
Total senior notes	4,558,000,000	4,550,000,000
Mortgage notes payable	62,000,000	64,000,000
Capital leases and other	17,000,000	18,000,000
Debt issuance costs	(66,000,000)	(77,000,000)
Total debt	4,721,000,000	4,655,000,000
Less current portion	(4,000,000)	(4,000,000)
Long-term debt	4,717,000,000	4,651,000,000
Revolving credit agreement
Debt Instrument [Line Items]
Revolving credit agreement	150,000,000	100,000,000
Senior Notes | $1,400 million 5.625% Senior notes, due February 15, 2021
Debt Instrument [Line Items]
Debt, face amount	$ 1,400,000,000
Interest rate, stated	5.625%
Senior notes	$ 1,400,000,000	1,400,000,000
Senior Notes | $1,000 million 4.75% Senior notes, due May 15, 2022
Debt Instrument [Line Items]
Debt, face amount	$ 1,000,000,000
Interest rate, stated	4.75%
Senior notes	$ 1,007,000,000	1,008,000,000
Senior Notes | $1,000 million 6.125% Senior notes, due February 15, 2024
Debt Instrument [Line Items]
Debt, face amount	$ 1,000,000,000
Interest rate, stated	6.125%
Senior notes	$ 1,000,000,000	1,000,000,000
Senior Notes | $1,200 million 4.75% Senior notes, due January 15, 2025
Debt Instrument [Line Items]
Debt, face amount	$ 1,200,000,000		$ 1,200,000,000
Interest rate, stated	4.75%		4.75%
Senior notes	$ 1,200,000,000	$ 1,200,000,000

Debt - (Interest Rate Swaps) (D

Debt - (Interest Rate Swaps) (Details) - USD ($)	Sep. 30, 2017	Feb. 28, 2017	Nov. 30, 2016
Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	$ 2,700,000,000
Average variable rate, interest rate swap agreements (percent)	3.61%
Weighted average rate, interest rate swap agreements (percent)	4.91%
February 15, 2021 Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	$ 600,000,000
May 15, 2022 Expiration, Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	500,000,000
February 15, 2024 Expiration Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	1,000,000,000
January 15, 2025 Expiration Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	600,000,000	$ 600,000,000
Average variable rate, interest rate swap agreements (percent)		2.53%
Senior Notes | $1,200 million 4.75% Senior notes, due January 15, 2025
Debt Instrument [Line Items]
Debt, face amount	$ 1,200,000,000		$ 1,200,000,000
Interest rate, stated	4.75%		4.75%

Debt - (Revolving Credit Agreem

Debt - (Revolving Credit Agreement) (Details) - Revolving credit agreement	9 Months Ended
	Sep. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,000,000,000
Borrowings outstanding	$ 150,000,000	$ 100,000,000
Weighted average interest rate (percent)	4.75%
Ratio of debt to EBITDA, after current year	3

Debt - (Letters of Credit & Sur

Debt - (Letters of Credit & Surety Bonds) (Details) € in Millions, $ in Millions	Sep. 30, 2017USD ($)	Sep. 30, 2017EUR (€)
Surety Bond
Debt Instrument [Line Items]
Surety bonds	$ 404
Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding	$ 51
Letters of credit, effective yield (percent)	1.33%	1.33%
Letter of Credit | Ribera Salud
Debt Instrument [Line Items]
Borrowings outstanding	$ 45	€ 38

Debt - (Construction Loan) (Det

Debt - (Construction Loan) (Details)	1 Months Ended
	Oct. 23, 2017USD ($)
Subsequent Event [Line Items]
Debt Instrument, Maturity Date	Apr. 23, 2021
Construction Loan Payable | Subsequent Event
Subsequent Event [Line Items]
Debt, face amount	$ 200,000,000
Optional extension term	1 year
Construction Loan Payable | London Interbank Offered Rate (LIBOR) | Subsequent Event
Subsequent Event [Line Items]
Interest rate	2.70%

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings attributable to Centene Corporation:
Earnings from continuing operations, net of tax	$ 205	$ 148	$ 598	$ 304
Discontinued operations, net of tax	0	(1)	0	(3)
Net earnings	$ 205	$ 147	$ 598	$ 301
Shares used in computing per share amounts:
Weighted average number of common shares outstanding (in shares)	172,508	170,775	172,314	155,681
Common stock equivalents (as determined by applying the treasury stock method) (in shares)	4,407	4,720	4,100	4,376
Weighted average number of common shares and potential dilutive common shares outstanding (in shares)	176,915	175,495	176,414	160,057
Basic:
Continuing operations (in dollars per share)	$ 1.19	$ 0.87	$ 3.47	$ 1.95
Discontinued operations (in dollars per share)	0	(0.01)	0	(0.02)
Basic earnings per common share (in dollars per share)	1.19	0.86	3.47	1.93
Diluted:
Continuing operations (in dollars per share)	1.16	0.84	3.39	1.90
Discontinued operations (in dollars per share)	0	0	0	(0.02)
Diluted earnings per common share (in dollars per share)	$ 1.16	$ 0.84	$ 3.39	$ 1.88
Anti-dilutive restricted stock and restricted stock units excluded from the calculation of diluted earnings per common share (in shares)	4	57	27	66

Segment Information (Details)

Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)segment	Sep. 30, 2016USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			2
Segment Reporting Information [Line Items]
Total revenues	$ 11,898	$ 10,846	$ 35,576	$ 28,696
Earnings from operations	340	342	1,018	739
Eliminations
Segment Reporting Information [Line Items]
Total revenues	(2,378)	(1,580)	(7,145)	(4,527)
Managed Care
Segment Reporting Information [Line Items]
Total revenues	11,248	10,175	33,704	26,926
Earnings from operations	238	309	799	627
Managed Care | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	11,259	10,231	33,737	27,070
Managed Care | Eliminations
Segment Reporting Information [Line Items]
Total revenues	11	56	33	144
Specialty Services
Segment Reporting Information [Line Items]
Total revenues	650	671	1,872	1,770
Earnings from operations	102	33	219	112
Specialty Services | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	3,017	2,195	8,984	6,153
Specialty Services | Eliminations
Segment Reporting Information [Line Items]
Total revenues	$ 2,367	$ 1,524	$ 7,112	$ 4,383

Contingencies (Details)

Contingencies (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Undiscounted estimated share of the guaranty	$ 56

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event - National Full-service Specialty Pharmacy $ in Millions	Oct. 01, 2017USD ($)
Subsequent Event [Line Items]
Percentage of ownership interests acquired	80.00%
Cash paid to acquire business	$ 53
Deferred consideration	7
Contingent consideration	$ 32