Taiwan Semiconductor Manufacturing Company Limited (TSM) 20-F 16 Apr 21 2020 FY Annual report (foreign) Financial data

Cover

Cover	12 Months Ended
	Dec. 31, 2020shares
Cover [Abstract]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	TSM
Entity Registrant Name	TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD
Entity Central Index Key	0001046179
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	25,930,380,458
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Document Registration Statement	false
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Title of 12(b) Security	Common Shares
Security Exchange Name	NYSE
Entity Address, Country	TW
Entity Incorporation, State or Country Code	F5
Entity Shell Company	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true

Consolidated Statements of Fina

Consolidated Statements of Financial Position $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
CURRENT ASSETS
Cash and cash equivalents	$ 660,170.6	$ 23,510.4	$ 455,399.3
Financial assets at fair value through profit or loss	2,259.4	80.4	326.8
Financial assets at fair value through other comprehensive income	122,448.5	4,360.7	127,396.6
Financial assets at amortized cost	6,598	235	299.9
Hedging financial assets	0.1		25.9
Notes and accounts receivable, net	145,480.3	5,180.9	138,908.6
Receivables from related parties	558.1	19.9	862.1
Other receivables from related parties	50.6	1.8	51.6
Inventories	137,353.4	4,891.5	82,981.2
Other financial assets	10,676.1	380.2	11,041.1
Other current assets	6,590.2	234.7	5,320.8
Total current assets	1,092,185.3	38,895.5	822,613.9
NONCURRENT ASSETS
Financial assets at fair value through other comprehensive income	4,514.9	160.8	4,124.3
Financial assets at amortized cost	4,372.2	155.7	7,348.9
Investments accounted for using equity method	18,730.2	667	18,618.8
Property, plant and equipment	1,555,589.1	55,398.5	1,352,377.4
Right-of-use assets	27,728.5	987.5	17,232.4
Intangible assets	25,768.1	917.7	20,653
Deferred income tax assets	25,958.2	924.4	17,928.4
Refundable deposits	1,343	47.8	2,085
Other noncurrent assets	4,411	157.1	1,742.9
Total noncurrent assets	1,668,415.2	59,416.5	1,442,111.1
TOTAL	2,760,600.5	98,312	2,264,725
CURRENT LIABILITIES
Short-term loans	88,559	3,153.8	118,522.3
Financial liabilities at fair value through profit or loss	94.1	3.4	982.3
Hedging financial liabilities	1.2	0.1	1.8
Accounts payable	38,987.3	1,388.4	38,771.1
Payables to related parties	2,107.7	75.1	1,434.9
Salary and bonus payable	20,071.2	714.8	16,272.3
Accrued profit sharing bonus to employees and compensation to directors and supervisors	35,681	1,270.7	23,648.9
Payables to contractors and equipment suppliers	157,805	5,619.8	140,810.7
Cash dividends payable	129,652	4,617.2	129,652
Income tax payable	68,656.7	2,445	40,094.3
Long-term liabilities - current portion	2,600	92.6	31,800
Accrued expenses and other current liabilities	87,683.2	3,122.6	56,373.2
Total current liabilities	631,898.4	22,503.5	598,363.8
NONCURRENT LIABILITIES
Bonds payable	254,105.1	9,049.3	25,100
Long-term bank loans	1,967.6	70.1
Deferred income tax liabilities	1,729.9	61.6	344.4
Lease liabilities	20,560.6	732.2	15,041.8
Net defined benefit liability	11,914.1	424.3	9,182.5
Guarantee deposits	265.6	9.5	176.9
Others	2,395.4	85.3	2,128.3
Total noncurrent liabilities	292,938.3	10,432.3	51,973.9
Total liabilities	924,836.7	32,935.8	650,337.7
EQUITY ATTRIBUTABLE TO SHAREHOLDERS OF THE PARENT
Capital stock	259,303.8	9,234.5	259,303.8
Capital surplus	56,347.2	2,006.7	56,339.7
Retained earnings
Appropriated as legal capital reserve	311,147	11,080.7	311,147
Appropriated as special capital reserve	42,259.1	1,505	10,675.1
Unappropriated earnings	1,220,434	43,462.7	1,003,808.3
Total retained earnings	1,573,840.1	56,048.4	1,325,630.4
Others	(54,679.8)	(1,947.3)	(27,568.3)
Equity attributable to shareholders of the parent	1,834,811.3	65,342.3	1,613,705.6
NON - CONTROLLING INTERESTS	952.5	33.9	681.7
Total equity	1,835,763.8	65,376.2	1,614,387.3
TOTAL	$ 2,760,600.5	$ 98,312	$ 2,264,725

Consolidated Statements of Prof

Consolidated Statements of Profit or Loss and Other Comprehensive Income $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)$ / shares	Dec. 31, 2020USD ($)$ / shares	Dec. 31, 2019TWD ($)$ / shares	Dec. 31, 2018TWD ($)$ / shares
Statement [LineItems]
NET REVENUE	$ 1,339,254.8	$ 47,694.3	$ 1,069,985.4	$ 1,031,473.6
COST OF REVENUE	628,108.4	22,368.6	577,286.9	533,487.5
GROSS PROFIT BEFORE REALIZED (UNREALIZED) GROSS PROFIT ON SALES TO ASSOCIATES	711,146.4	25,325.7	492,698.5	497,986.1
REALIZED (UNREALIZED) GROSS PROFIT ON SALES TO ASSOCIATES	(16.3)	(0.6)	3.4	(111.8)
GROSS PROFIT	711,130.1	25,325.1	492,701.9	497,874.3
OPERATING EXPENSES
Research and development	109,486	3,899.1	91,418.7	85,895.6
General and administrative	28,457.6	1,013.4	21,737.2	20,265.9
Marketing	7,112.8	253.3	6,348.6	5,987.8
Total operating expenses	145,056.4	5,165.8	119,504.5	112,149.3
OTHER OPERATING INCOME AND EXPENSES, NET	710	25.3	(496.3)	(2,101.5)
INCOME FROM OPERATIONS	566,783.7	20,184.6	372,701.1	383,623.5
NON-OPERATING INCOME AND EXPENSES
Share of profits of associates	3,562	126.8	2,861	3,090.6
Interest Income	9,018.4	321.2	16,189.4	14,694.4
Other income	660.6	23.4	417.3	158.4
Foreign exchange gain (loss), net	(3,303.3)	(117.6)	2,095.2	2,438.2
Finance costs	(2,081.5)	(74.1)	(3,250.9)	(3,051.2)
Other gains and losses, net	10,106.4	360	(1,151)	(3,410.8)
Total non-operating income and expenses	17,962.6	639.7	17,161	13,919.6
INCOME BEFORE INCOME TAX	584,746.3	20,824.3	389,862.1	397,543.1
INCOME TAX EXPENSE	73,738.3	2,626	35,835.1	34,436.9
NET INCOME	511,008	18,198.3	354,027	363,106.2
OTHER COMPREHENSIVE INCOME (LOSS) - Items that will not be reclassified subsequently to profit or loss
Remeasurement of defined benefit obligation	(3,516.8)	(125.2)	253.9	(861.2)
Unrealized gain/(loss) on investments in equity instruments at fair value through other comprehensive income	423.7	15.1	334.3	(3,309.1)
Gain (loss) on hedging instruments	24.1	0.9	(109.6)	41
Share of other comprehensive loss of associates	(11.6)	(0.4)	(18.2)	(14.2)
Income tax benefit (expense) related to items that will not be reclassified subsequently	422.7	15	(21)	195.7
Total items that will not be reclassified subsequently to profit or loss	(2,657.9)	(94.6)	439.4	(3,947.8)
OTHER COMPREHENSIVE INCOME (LOSS) - Items that may be reclassified subsequently to profit or loss
Exchange differences arising on translation of foreign operations	(29,847.2)	(1,062.9)	(14,689.1)	14,562.4
Unrealized gain/(loss) on investments in debt instruments at fair value through other comprehensive income	2,466.7	87.8	2,566.4	(870.9)
Share of other comprehensive income (loss) of associates	(283.4)	(10.1)	(140.2)	93.3
Total items that may be reclassified subsequently to profit or loss	(27,663.9)	(985.2)	(12,262.9)	13,784.8
Other comprehensive income (loss) for the year, net of income tax	(30,321.8)	(1,079.8)	(11,823.5)	9,837
TOTAL COMPREHENSIVE INCOME FOR THE YEAR	480,686.2	17,118.5	342,203.5	372,943.2
NET INCOME ATTRIBUTABLE TO:
Shareholders of the parent	510,744	18,188.9	353,948	363,052.7
Non-controlling interests	264	9.4	79	53.5
NET INCOME	511,008	18,198.3	354,027	363,106.2
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO:
Shareholders of the parent	480,422.1	17,109	342,124.9	372,886.8
Non-controlling interests	264.1	9.5	78.6	56.4
TOTAL COMPREHENSIVE INCOME FOR THE YEAR	$ 480,686.2	$ 17,118.5	$ 342,203.5	$ 372,943.2
EARNINGS PER SHARE
Basic earnings per share | (per share)	$ 19.70	$ 0.70	$ 13.65	$ 14
Diluted earnings per share | (per share)	19.70	0.70	13.65	14
American Depositary Shares (one represents five common shares) [member]
EARNINGS PER SHARE
Basic earnings per share | (per share)	98.48	3.51	68.25	70.01
Diluted earnings per share | (per share)	$ 98.48	$ 3.51	$ 68.25	$ 70.01

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity shares in Millions, $ in Millions, $ in Millions	TWD ($)	USD ($)	Capital Stock - Common Stock [member]TWD ($)shares	Capital Stock - Common Stock [member]USD ($)shares	Capital Surplus [member]TWD ($)	Capital Surplus [member]USD ($)	Retained Earnings - Legal Capital Reserve [member]TWD ($)	Retained Earnings - Legal Capital Reserve [member]USD ($)	Retained Earnings - Special Capital Reserve [member]TWD ($)	Retained Earnings - Special Capital Reserve [member]USD ($)	Retained Earnings - Unappropriated Earnings [member]TWD ($)	Retained Earnings - Unappropriated Earnings [member]USD ($)	Retained Earnings [member]TWD ($)	Retained Earnings [member]USD ($)	Others - Foreign Currency Translation Reserve [member]TWD ($)	Others - Foreign Currency Translation Reserve [member]USD ($)	Other - Unrealized Gain (Loss) on Financial Assets at Fair Value Through Other Comprehensive Income [member]TWD ($)	Other - Unrealized Gain (Loss) on Financial Assets at Fair Value Through Other Comprehensive Income [member]USD ($)	Other - Gain (Loss) on Hedging Instruments [member]TWD ($)	Other - Gain (Loss) on Hedging Instruments [member]USD ($)	Others - Unearned Stock-Based Employee Compensation [member]TWD ($)	Others - Unearned Stock-Based Employee Compensation [member]USD ($)	Others - Total [member]TWD ($)	Others - Total [member]USD ($)	Total Equity Attributable to Shareholders of the Parent [member]TWD ($)	Total Equity Attributable to Shareholders of the Parent [member]USD ($)	Non-controlling Interests [member]TWD ($)	Non-controlling Interests [member]USD ($)
Beginning balance at Dec. 31, 2017	$ 1,495,692.3		$ 259,303.8		$ 56,309.6		$ 241,722.7				$ 964,884.9		$ 1,206,607.6		$ (26,697.7)		$ (524.9)		$ 4.2		$ (10.3)		$ (27,228.7)		$ 1,494,992.3		$ 700
Beginning balance, shares at Dec. 31, 2017 | shares			25,930.3	25,930.3
Legal capital reserve							34,311.2				(34,311.2)
Special capital reserve									$ 26,907.5		(26,907.5)
Cash dividends to shareholders	(207,443)										(207,443)		(207,443)												(207,443)
Total	(207,443)						34,311.2		26,907.5		(268,661.7)		(207,443)												(207,443)
Net income(loss)	363,106.2										363,052.7		363,052.7												363,052.7		53.5
Other comprehensive income (loss), net of income tax	9,837										(765.3)		(765.3)		14,655.3		(4,097.5)		41.6				10,599.4		9,834.1		2.9
Total comprehensive income (loss)	372,943.2										362,287.4		362,287.4		14,655.3		(4,097.5)		41.6				10,599.4		372,886.8		56.4
Disposal of investments in equity instruments at fair value through other comprehensive income											(1,193.1)		(1,193.1)				1,193.1						1,193.1
Basis adjustment for loss on hedging instruments	(22.2)																		(22.2)				(22.2)		(22.2)
Adjustments to share of changes in equities of associates	2.1				(6.4)																8.5		8.5		2.1
From share of changes in equities of subsidiaries					2.7																				2.7		(2.7)
Donation from shareholders	10.1				10.1																				10.1
Increase (Decrease) in non-controlling interests	(77.4)																										(77.4)
Ending balance at Dec. 31, 2018	1,661,105.1		$ 259,303.8		56,316		276,033.9		26,907.5		1,057,317.5		1,360,258.9		(12,042.4)		(3,429.3)		23.6		(1.8)		(15,449.9)		1,660,428.8		676.3
Ending balance, shares at Dec. 31, 2018 | shares			25,930.3	25,930.3
Legal capital reserve							35,113.1				(35,113.1)
Special capital reserve									(16,232.4)		16,232.4
Cash dividends to shareholders	(388,955.7)										(388,955.7)		(388,955.7)												(388,955.7)
Total	(388,955.7)						35,113.1		(16,232.4)		(407,836.4)		(388,955.7)												(388,955.7)
Net income(loss)	354,027										353,948		353,948												353,948		79
Other comprehensive income (loss), net of income tax	(11,823.5)										217.1		217.1		(14,829)		2,898.5		(109.7)				(12,040.2)		(11,823.1)		(0.4)
Total comprehensive income (loss)	342,203.5										354,165.1		354,165.1		(14,829)		2,898.5		(109.7)				(12,040.2)		342,124.9		78.6
Disposal of investments in equity instruments at fair value through other comprehensive income											162.1		162.1				(162.1)						(162.1)
Basis adjustment for loss on hedging instruments	82.3																		82.3				82.3		82.3
Adjustments to share of changes in equities of associates	21.2				19.4																1.6		1.6		21		0.2
From share of changes in equities of subsidiaries					0.3																				0.3		(0.3)
Donation from shareholders	4				4																				4
Increase (Decrease) in non-controlling interests	(73.1)																										(73.1)
Ending balance at Dec. 31, 2019	1,614,387.3		$ 259,303.8		56,339.7		311,147		10,675.1		1,003,808.3		1,325,630.4		(26,871.4)		(692.9)		(3.8)		(0.2)		(27,568.3)		1,613,705.6		681.7
Ending balance, shares at Dec. 31, 2019 | shares			25,930.3	25,930.3
Special capital reserve									31,584		(31,584)
Cash dividends to shareholders	(259,303.8)										(259,303.8)		(259,303.8)												(259,303.8)
Total	(259,303.8)								31,584		(290,887.8)		(259,303.8)												(259,303.8)
Net income(loss)	511,008	$ 18,198.3									510,744		510,744												510,744		264
Other comprehensive income (loss), net of income tax	(30,321.8)	(1,079.8)									(3,121.8)		(3,121.8)		(30,130.2)		2,906		24.1				(27,200.1)		(30,321.9)		0.1
Total comprehensive income (loss)	480,686.2	17,118.5									507,622.2		507,622.2		(30,130.2)		2,906		24.1				(27,200.1)		480,422.1		264.1
Disposal of investments in equity instruments at fair value through other comprehensive income											(108.7)		(108.7)				108.7						108.7
Basis adjustment for loss on hedging instruments	(20.3)																		$ (20.3)				(20.3)		(20.3)
Adjustments to share of changes in equities of associates	0.5				0.3																$ 0.2		0.2		0.5
Donation from shareholders	7.2				7.2																				7.2
Increase (Decrease) in non-controlling interests	6.7																										6.7
Ending balance at Dec. 31, 2020	$ 1,835,763.8	$ 65,376.2	$ 259,303.8	$ 9,234.5	$ 56,347.2	$ 2,006.7	$ 311,147	$ 11,080.7	$ 42,259.1	$ 1,505	$ 1,220,434	$ 43,462.7	$ 1,573,840.1	$ 56,048.4	$ (57,001.6)	$ (2,030)	$ 2,321.8	$ 82.7					$ (54,679.8)	$ (1,947.3)	$ 1,834,811.3	$ 65,342.3	$ 952.5	$ 33.9
Ending balance, shares at Dec. 31, 2020 | shares			25,930.3	25,930.3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Income before income tax	$ 584,746.3	$ 20,824.3	$ 389,862.1	$ 397,543.1
Adjustments for:
Depreciation expense	324,538.4	11,557.6	281,411.8	288,124.9
Amortization expense	7,186.2	255.9	5,472.4	4,421.4
Expected credit losses recognized (reversal) on investments in debt instruments	3.7	0.1	1.7	(2.4)
Finance costs	2,081.5	74.1	3,250.9	3,051.2
Share of profits of associates	(3,562)	(126.8)	(2,861)	(3,090.6)
Interest income	(9,018.4)	(321.2)	(16,189.4)	(14,694.4)
Share-based compensation	6.6	0.2	2.8
Loss (gain) on disposal or retirement of property, plant and equipment, net	(188.9)	(6.7)	950	1,005.6
Loss (gain) on disposal of intangible assets, net	0.6		2.4	(0.4)
Impairment loss (reversal of impairment loss) on property, plant and equipment	10.2	0.4	(301.4)	423.5
Loss (gain) on financial instruments at fair value through profit or loss, net	(3)	(0.1)	955.7	358.2
Loss (gain) on disposal of investments in debt instruments at fair value through other comprehensive income, net	(1,439.4)	(51.3)	(537.8)	989.1
Loss from disposal of subsidiaries			4.6
Unrealized (realized) gross profit on sales to associates	16.3	0.6	(3.4)	111.8
Loss (gain) on foreign exchange, net	(1,372.6)	(48.9)	(5,228.2)	2,916.7
Dividend income	(637.6)	(22.7)	(417.3)	(158.4)
Loss (gain) arising from fair value hedges, net			(13.1)	2.3
Gain on lease modification	(2.8)	(0.1)	(2.1)
Changes in operating assets and liabilities:
Financial instruments at fair value through profit or loss	(2,965.2)	(105.6)	848.8	480.1
Notes and accounts receivable, net	(8,082.7)	(287.8)	(18,119.6)	(13,271.3)
Receivables from related parties	304	10.8	(277.7)	599.7
Other receivables from related parties	7.6	0.3	13.4	106.1
Inventories	(54,372.2)	(1,936.3)	20,249.8	(29,370)
Other financial assets	1,389.5	49.5	3,383.5	(4,601.3)
Other current assets	(1,358.1)	(48.4)	(76.3)	(513)
Other noncurrent assets				152.6
Accounts payable	404.6	14.4	5,860.1	4,540.6
Payables to related parties	672.8	24	58.4	(279.9)
Salary and bonus payable	3,798.9	135.3	1,800.9	216.5
Accrued profit sharing bonus to employees and compensation to directors and supervisors	12,032.1	428.5	(332.2)	562
Accrued expenses and other current liabilities	20,617.4	734.2	(2,372)	(20,226.4)
Net defined benefit liability	(785.2)	(28)	(215)	(60.5)
Cash generated from operations	874,028.6	31,126.3	667,182.8	619,336.8
Income taxes paid	(51,362.4)	(1,829.1)	(52,044.1)	(45,382.5)
Net cash generated by operating activities	822,666.2	29,297.2	615,138.7	573,954.3
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisitions of financial instruments at fair value through profit or loss - debt instruments			(124.7)	(310.5)
Acquisitions of financial assets at fair value through other comprehensive income	(262,637.5)	(9,353.2)	(257,558.2)	(96,412.8)
Acquisitions of financial assets at amortized cost	(4,302.8)	(153.2)	(313.9)	(2,294.1)
Acquisitions of property, plant and equipment	(507,238.7)	(18,064.1)	(460,422.2)	(315,581.9)
Acquisitions of intangible assets	(9,542.4)	(339.8)	(9,329.9)	(7,100.3)
Proceeds from disposal or redemption of financial instruments at fair value through profit or loss - debt instruments	30	1.1	2,418.2	487.2
Proceeds from disposal or redemption of financial assets at fair value through other comprehensive income	266,931.9	9,506.1	230,444.5	86,639.3
Proceeds from disposal or redemption of financial assets at amortized cost	285.2	10.2	14,349.2	2,032.4
Proceeds from disposal or redemption of property, plant and equipment	606.7	21.6	287.3	181.5
Proceeds from disposal or redemption of intangible assets				0.5
Proceeds from return of capital of investments in equity instruments at fair value through other comprehensive income	51.1	1.8	1.1	127.9
Derecognition of hedging financial instruments	(308.8)	(11)	(436.6)	250.5
Interest received	9,775.1	348.1	16,875	14,660.4
Other dividends received	735.1	26.2	320.2	158.4
Dividends received from investments accounted for using equity method	2,752.1	98	1,719	3,262.9
Increase in prepayments for leases	(4,693.4)	(167.1)
Refundable deposits paid	(726.9)	(25.9)	(1,465.8)	(2,227.5)
Refundable deposits refunded	1,431.9	51	1,019.3	1,857.2
Net cash used in investing activities	(505,781.7)	(18,012.1)	(458,801.6)	(314,268.9)
CASH FLOWS FROM FINANCING ACTIVITIES
Increase (decrease) in short-term loans	(31,571.6)	(1,124.3)	31,804.3	23,923
Proceeds from short-term bills payable	7,485.3	266.6
Repayments of short-term bills payable	(7,500)	(267.1)
Proceeds from issuance of bonds	236,725.7	8,430.4
Repayment of bonds	(31,800)	(1,132.5)	(34,900)	(58,024.9)
Proceeds from long-term bank loans	2,000	71.2
Payments for transaction costs attributable to the issuance of bonds	(390.7)	(13.9)
Repayment of the principal portion of lease liabilities	(2,615.7)	(93.2)	(2,930.6)
Interest paid	(1,781.1)	(63.4)	(3,597.1)	(3,233.4)
Guarantee deposits received	145.6	5.2	62.2	1,668.9
Guarantee deposits refunded	(16.1)	(0.6)	(701.3)	(1,948.1)
Cash dividends	(259,303.8)	(9,234.5)	(259,303.8)	(207,443)
Donation from shareholders	7.3	0.3	4	10.1
Decrease in non-controlling interests			(75.9)	(77.4)
Net cash used in financing activities	(88,615.1)	(3,155.8)	(269,638.2)	(245,124.8)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(23,498.1)	(836.8)	(9,114.2)	9,862.3
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	204,771.3	7,292.5	(122,415.3)	24,422.9
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	455,399.3	16,217.9	577,814.6	553,391.7
CASH AND CASH EQUIVALENTS, END OF YEAR	660,170.6	23,510.4	455,399.3	$ 577,814.6
Land use right and others [member]
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from government grants	25.4	0.9	850.6
Property, plant and equipment [member]
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from government grants	$ 1,044.3	$ 37.2	$ 2,565.3

General

General	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
General	1. GENERAL Taiwan Semiconductor Manufacturing Company Limited (TSMC), a Republic of China (R.O.C.) corporation, was incorporated on February 21, 1987. TSMC is a dedicated foundry in the semiconductor industry which engages mainly in the manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing of masks. On September 5, 1994, TSMC’s shares were listed on the Taiwan Stock Exchange (TWSE). On October 8, 1997, TSMC listed some of its shares of stock on the New York Stock Exchange (NYSE) in the form of American Depositary Shares (ADSs). The address of its registered office and principal place of business is No. 8, Li-Hsin

The Authorization of Financial

The Authorization of Financial Statements	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
The Authorization of Financial Statements	2. THE AUTHORIZATION OF FINANCIAL STATEMENTS The accompanying consolidated financial statements were authorized for issue by the management on April 16, 2021.

U.S. Dollar Amounts

U.S. Dollar Amounts	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
U.S. Dollar Amounts	3. U.S. DOLLAR AMOUNTS TSMC and its subsidiaries (collectively as the “Company”) maintain its accounts and express its consolidated financial statements in New Taiwan dollars. For convenience only, U.S. dollar amounts presented in the accompanying consolidated financial statements have been translated from New Taiwan dollars at the exchange rate as set forth in the statistical release of the Federal Reserve Board of the Unites States, which was NT$28.08 to US$1.00 as of December 31, 2020. The convenience translations should not be construed as representations that the New Taiwan dollar amounts have been, could have been, or could in the future be, converted into U.S. dollars at this or any other rate of exchange.

Application of New and Revised

Application of New and Revised IFRS, IAS, IFRIC, and SIC Issued by the IASB (collectively, "IFRSs")	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Application of New and Revised IFRS, IAS, IFRIC, and SIC Issued by the IASB (collectively, "IFRSs")	4. APPLICATION OF NEW AND REVISED INTERNATIONAL FINANCIAL REPORTING STANDARDS (IFRS), INTERNATIONAL ACCOUNTING STANDARDS (IAS), IFRIC INTERPRETATIONS (IFRIC), AND SIC INTERPRETATIONS (SIC) ISSUED BY THE INTERNATIONAL ACCOUNTING STANDARDS BOARD (IASB) (collectively, “IFRSs”). a. Amendments to IFRSs and the new interpretation that are mandatorily effective for the current year New, Revised or Amended Standards and Interpretations Effective Date Issued Amendments to IFRS 3 “Definition of a Business” January 1, 2020 (Note 1) Amendments to IFRS 9, IAS 39 and IFRS 7 “Interest Rate Benchmark Reform” January 1, 2020 (Note 2) Amendments to IAS 1 and IAS 8 “Definition of Material” January 1, 2020 (Note 3) Amendment to IFRS 16 “Covid-19-Related June 1, 2020 (Note 4) Note 1: The Company shall apply these a m Note 2: The Company shall apply these amendments retrospectively for annual reporting periods beginning on or after January 1, 2020. Note 3: The Company shall apply these amendments prospectively for annual reporting periods beginning on or after January 1, 2020. Note 4: The Company shall apply these amendments for annual reporting periods beginning on or after June 1, 2020. The Company has early adopted the amendments on January 1, 2020. The Company believes that the adoption of aforementioned standards or interpretations did not have a significant effect on the Company’s accounting policies b. New and revised standards, amendments and interpretations in issue but not yet effective New, Revised or Amended Standards and Interpretations Effective Date Issued Annual Improvements to IFRS Standards 2018–2020 January 1, 2022 Amendments to IFRS 3 “Reference to the Conceptual Framework” January 1, 2022 Amendments to IFRS 9, IAS 39, IFRS 7 and IFRS 16 “Interest Rate Benchmark Reform - Phase 2” January 1, 2021 Amendments to IFRS 10 and IAS 28 “Sale or Contribution of Assets between an Investor and its Associate or Joint Venture” To be determined by IASB Amendments to IAS 1 “Classification of Liabilities as Current or Non-current” January 1, 2023 Amendments to IAS 1 “Disclosure of Accounting Policies” January 1, 2023 Amendments to IAS 8 “Definition of Accounting Estimates” January 1, 2023 Amendments to IAS 16 “Property, Plant and Equipment - Proceeds before Intended Use” January 1, 2022 Amendments to IAS 37 “Onerous Contracts–Cost of Fulfilling a Contract” January 1, 2022 As of the date the accompanying consolidated financial statements were authorized for issue, the Company continues in evaluating the impact on its financial position and financial performance as a result of the initial adoption of the aforementioned standards or interpretations and related applicable period. The related impact will be disclosed when the Company completes the evaluation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Significant Accounting Policies	5. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant accounting policies are summarized as follows: Statement of Compliance The accompanying consolidated financial statements have been prepared in accordance with IFRSs. Basis of Preparation The accompanying consolidated financial statements have been prepared on the historical cost basis except for financial instruments that are measured at fair values, as explained in the accounting policies below. Historical cost is generally based on the fair value of the consideration given in exchange for the assets. Basis of Consolidation The basis for the consolidated financial statements The consolidated financial statements incorporate the financial statements of TSMC and entities controlled by TSMC (its subsidiaries). Income and expenses of subsidiaries acquired or disposed of are included in the consolidated statements of profit or loss and other comprehensive income from the effective date of acquisition and up to the effective date of disposal, as appropriate. Total comprehensive income of subsidiaries is attributed to the shareholders of the parent and to the non-controlling interests even if this results in the non-controlling interests having a deficit balance. When necessary, adjustments are made to the financial statements of subsidiaries to bring their accounting policies into line with those used by the Company. All intra-group transactions, balances, income and expenses are eliminated in full on consolidation. Changes in the Company’s ownership interests in subsidiaries that do not result in the Company losing control over the subsidiaries are accounted for as equity transactions. The carrying amounts of the Company’s interests and the non-controlling interests are adjusted to reflect the changes in their relative interests in the subsidiaries. Any difference between the amount by which the non-controlling interests are adjusted and the fair value of the consideration paid or received is recognized directly in equity and attributed to shareholders of the parent. When the Company loses control of a subsidiary, a gain or loss is recognized in profit or loss and is calculated as the difference between: a. the aggregate of the fair value of consideration received and the fair value of any retained interest at the date when control is lost; and b. the previous carrying amount of the assets (including goodwill), and liabilities of the subsidiary and any non-controlling interest. The Company shall account for all amounts recognized in other comprehensive income in relation to the subsidiary on the same basis as would be required if the Company had directly disposed of the related assets and liabilities. The fair value of any investment retained in the former subsidiary at the date when control is lost is regarded as the cost on initial recognition of an investment in an associate. The subsidiaries in the consolidated financial statements The detail information of the subsidiaries at the end of reporting period was as follows: Percentage of Ownership Name of Investor Name of Investee Main Businesses and Products Establishment and Operating December 31, 2019 December 31, 2020 Note TSMC TSMC North America Selling and marketing of integrated circuits and other semiconductor devices San Jose, California, U.S.A. 100% 100% — TSMC Europe B.V. (TSMC Europe) Customer service and supporting activities Amsterdam, the Netherlands 100% 100% a) TSMC Japan Limited (TSMC Japan) Customer service and supporting activities Yokohama, Japan 100% 100% a) TSMC Design Technology Japan, Inc. (TSMC JDC) Engineering support activities Yokohama, Japan — 100% a), b) TSMC Korea Limited (TSMC Korea) Customer service and supporting activities Seoul, Korea 100% 100% a) TSMC TSMC Partners, Ltd. (TSMC Partners) Investing in companies involved in the design, manufacture, and other related business in the semiconductor industry and other investment activities Tortola, British Virgin Islands 100% 100% a) TSMC Global, Ltd. (TSMC Global) Investment activities Tortola, British Virgin Islands 100% 100% — TSMC China Company Limited (TSMC China) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Shanghai, China 100% 100% — TSMC Nanjing Company Limited (TSMC Nanjing) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Nanjing, China 100% 100% d) VisEra Technologies Company Ltd. (VisEra Tech) Engaged in manufacturing electronic spare parts and in researching, developing, designing, manufacturing, selling, packaging and testing of color filter Hsin-Chu, 87% 87% — TSMC Arizona Corporation (TSMC Arizona) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Phoenix, Arizona, U.S.A. — 100% a), c) VentureTech Alliance Fund II, L.P. (VTAF II) Investing in new start-up Cayman Islands 98% 98% a) VentureTech Alliance Fund III, L.P. (VTAF III) Investing in new start-up Cayman Islands 98% 98% a) TSMC Partners TSMC Development, Inc. (TSMC Development) Investing in companies involved in the manufacturing related business in the semiconductor industry Delaware, U.S.A. 100% 100% — TSMC Technology, Inc. (TSMC Technology) Engineering support activities Delaware, U.S.A. 100% 100% a) TSMC Design Technology Canada Inc. (TSMC Canada) Engineering support activities Ontario, Canada 100% 100% a) InveStar Semiconductor Development Fund, Inc. (ISDF) Investing in new start-up Cayman Islands 97% — a) , e) InveStar Semiconductor Development Fund, Inc. (II) LDC. (ISDF II) Investing in new start-up Cayman Islands 97% — a) , e) TSMC Development WaferTech, LLC (WaferTech) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Washington, U.S.A. 100% 100% — VTAF III Growth Fund Limited (Growth Fund) Investing in new start-up Cayman Islands 100% 100% a) Note a: This is an immaterial subsidiary for which the consolidated financial statements are not audited by the Company’s independent auditors. Note b: TSMC JDC has been established in January 2020. Note c: TSMC Arizona has been established in November 2020. Under the terms of the development agreement entered into between TSMC Arizona and the City of Phoenix in March 2021, the City of Phoenix commits approximately US$205 million toward various public infrastructure projects in the area of the proposed manufacturing facility, conditioned on TSMC Arizona’s achieving a minimum project scale with defined spending and job - Note d: Under the investment agreement entered into with the municipal government of Nanjing, China, the Company will make an investment in Nanjing in the amount of approximately US$3 billion to establish a subsidiary operating a 300mm wafer fab with the capacity of 20,000 12-inch 12-inch Note e: ISDF and ISDF II have completed the liquidation procedures in November 2020. Foreign Currencies The financial statements of each individual consolidated entity were expressed in the currency which reflected its primary economic environment (functional currency). The functional currency of TSMC In preparing the financial statements of each individual consolidated entity, transactions in currencies other than the entity’s functional currency (foreign currencies) are recognized at the rates of exchange prevailing at the dates of the transactions. At the end of each reporting period, monetary items denominated in foreign currencies are retranslated at the rates prevailing at that date. Such exchange differences are recognized in profit or loss in the year in which they arise. Non-monetary non-monetary non-monetary Non-monetary For the purposes of presenting consolidated financial statements, the assets and liabilities of the Company’s foreign operations are translated into NT$ using exchange rates prevailing at the end of each reporting period. Income and expense items are translated at the average exchange rates for the period. Exchange differences arising, if any, are recognized in other comprehensive income and accumulated in equity (attributed to non-controlling interests as appropriate). Classification of Current and Noncurrent Assets and Liabilities Current assets are assets held for trading purposes and assets expected to be converted to cash, sold or consumed within one year from the end of the reporting period. Current liabilities are obligations incurred for trading purposes and obligations expected to be settled within one year from the end of the reporting period. Assets and liabilities that are not classified as current are noncurrent assets and liabilities, respectively. Cash Equivalents Cash equivalents, for the purpose of meeting short-term cash commitments, consist of highly liquid time deposits and investments that are readily convertible to known amounts of cash and which are subject to an insignificant risk of changes in value. Financial Instruments Financial assets and liabilities shall be recognized when the Company becomes a party to the contractual provisions of the instruments. Financial assets and liabilities are initially recognized at fair values. Transaction costs that are directly attributable to the acquisition or issue of financial assets and financial liabilities (other than financial assets and financial liabilities at fair value through profit or loss) are added to or deducted from the fair value of the financial assets or financial liabilities, as appropriate, on initial recognition. Transaction costs directly attributable to the acquisition of financial assets or financial liabilities at fair value through profit or loss are recognized immediately in profit or loss. Financial Assets The classification of financial assets depends on the nature and purpose of the financial assets and is determined at the time of initial recognition. Regular way purchases or sales of financial assets are recognized and derecognized on a trade date or settlement date basis for which financial assets were classified in the same way, respectively. Regular way purchases or sales are purchases or sales of financial assets that require delivery of assets within the time frame established by regulation or convention in the marketplace. a. Category of financial assets and measurement Financial assets are classified into the following categories: financial assets at FVTPL, investments in debt instruments and equity instruments at FVTOCI, and financial assets at amortized cost. 1) Financial asset at FVTPL For certain financial assets which include debt instruments that do not meet the criteria of amortized cost or FVTOCI, it is mandatorily required to measure them at FVTPL. Any gain or loss arising from remeasurement is recognized in profit or loss. The net gain or loss recognized in profit or loss incorporates any interest earned on the financial asset. 2) Investments in debt instruments at FVTOCI Debt instruments with contractual terms specifying that cash flows are solely payments of principal and interest on the principal amount outstanding, together with objective of collecting contractual cash flows and selling the financial assets, are measured at FVTOCI. Interest income calculated using the effective interest method, foreign exchange gains and losses and impairment gains or losses on investments in debt instruments at FVTOCI are recognized in profit or loss. Other changes in the carrying amount of these debt instruments are recognized in other comprehensive income and will be reclassified to profit or loss when these debt instruments are disposed. 3) Investments in equity instruments at FVTOCI On initial recognition, the Company may irrevocably designate investments in equity investments that is not held for trading as at FVTOCI. Investments in equity instruments at FVTOCI are subsequently measured at fair value with gains and losses arising from changes in fair value recognized in other comprehensive income and accumulated in other equity. Dividends on these investments in equity instruments at FVTOCI are recognized in profit or loss when the Company’s right to receive the dividends is established, unless the Company’s rights clearly represent a recovery of part of the cost of the investment. 4) Measured at amortized cost Cash and cash equivalents, debt instrument investments, notes and accounts receivable (including related parties), other receivables and refundable deposits are measured at amortized cost. Debt instruments with contractual terms specifying that cash flows are solely payments of principal and interest on the principal amount outstanding, together with objective of holding financial assets in order to collect contractual cash flows, are measured at amortized cost. Subsequent to initial recognition, financial assets measured at amortized cost are measured at amortized cost, which equals to carrying amount determined by the effective interest method less any impairment loss. b. Impairment of financial assets At the end of each reporting period, a loss allowance for expected credit loss is recognized for financial assets at amortized cost (including accounts receivable) and for investments in debt instruments that are measured at FVTOCI. The loss allowance for accounts receivable is measured at an amount equal to lifetime expected credit losses. For financial assets at amortized cost and investments in debt instruments that are measured at FVTOCI, when the credit risk on the financial instrument has not increased significantly since initial recognition, a loss allowance is recognized at an amount equal to expected credit loss resulting from possible default events of a financial instrument within 12 months after the reporting date. If, on the other hand, there has been a significant increase in credit risk since initial recognition, a loss allowance is recognized at an amount equal to expected credit loss resulting from all possible default events over the expected life of a financial instrument. The Company recognizes an impairment loss in profit or loss for all financial instruments with a corresponding adjustment to their carrying amount through a loss allowance account, except for investments in debt instruments that are measured at FVTOCI, for which the loss allowance is recognized in other comprehensive income and does not reduce the carrying amount of the financial asset. c. Derecognition of financial assets The Company derecognizes a financial asset only when the contractual rights to the cash flows from the financial asset expire, or when it transfers the financial asset and substantially all the risks and rewards of ownership of the financial asset to another entity. On derecognition of a financial asset at amortized cost in its entirety, the difference between the asset’s carrying amount and the sum of the consideration received and receivable is recognized in profit or loss. On derecognition of an investment in a debt instrument at FVTOCI, the difference between the asset’s carrying amount and the sum of the consideration received and receivable and the cumulative gain or loss that had been recognized in other comprehensive income is recognized in profit or loss. However, on derecognition of an investment in an equity instrument at FVTOCI, the cumulative gain or loss that had been recognized in other comprehensive income is transferred directly to retained earnings, without recycling through profit or loss. Financial Liabilities and Equity Instruments Classification as debt or equity Debt and equity instruments issued by the Company are classified as either financial liabilities or as equity in accordance with the substance of the contractual arrangements and the definitions of a financial liability and an equity instrument. Equity instruments An equity instrument is any contract that evidences a residual interest in the assets of an entity after deducting all of its liabilities. Equity instruments issued by the Company are recognized at the proceeds received, net of direct issue costs. Financial liabilities Financial liabilities are subsequently measured either at amortized cost using effective interest method or at FVTPL. Financial liabilities are classified as at fair value through profit or loss when the financial liability is either held for trading or is designated as at fair value through profit or loss. Financial liabilities at fair value through profit or loss are stated at fair value, with any gains or losses arising on remeasurement recognized in profit or loss. Financial liabilities other than those held for trading purposes and designated as at FVTPL are subsequently measured at amortized cost at the end of each reporting period. Derecognition of financial liabilities The Company derecognizes financial liabilities when, and only when, the Company’s obligations are discharged, cancelled or they expire. The difference between the carrying amount of the financial liability derecognized and the consideration paid and payable is recognized in profit or loss. Derivative Financial Instruments Derivative financial instruments are initially recognized at fair value at the date the derivative contracts are entered into and are subsequently remeasured to their fair value at the end of each reporting period. The resulting gain or loss is recognized in profit or loss immediately unless the derivative financial instrument is designated and effective as a hedging instrument, in which event the timing of the recognition in profit or loss depends on the nature of the hedge relationship. Hedge Accounting a. Fair value hedge The Company designates certain hedging instruments, such as interest rate futures contracts, to partially hedge against the fair value change caused by interest rates fluctuation in the Company’s fixed income investments. Changes in the fair value of hedging instrument that are designated and qualify as fair value hedges are recognized in profit or loss immediately, together with any changes in the fair value of the hedged items that are attributable to the hedged risk. b. Cash flow hedge The Company designates certain hedging instruments, such as forward exchange contracts and foreign currency deposits, to partially hedge its foreign exchange rate risks associated with certain highly probable forecast transactions (capital expenditures). The effective portion of changes in the fair value of hedging instruments is recognized in other comprehensive income. When the forecast transactions actually take place, the associated gains or losses that were recognized in other comprehensive income are removed from equity and included in the initial cost of the hedged items. The gains or losses from hedging instruments relating to the ineffective portion are recognized immediately in profit or loss. The Company prospectively discontinues hedge accounting only when the hedging relationship ceases to meet the qualifying criteria; for instance, when the hedging instrument expires or is sold, terminated or exercised. Inventories Inventories are stated at the lower of cost or net realizable value. Inventories are recorded at standard cost and adjusted to approximate weighted-average cost at the end of the reporting period. Net realizable value represents the estimated selling price of inventories less all estimated costs of completion and costs necessary to make the sale. Investments Accounted for Using Equity Method Investments accounted for using the equity method are investments in associates. An associate is an entity over which the Company has significant influence and that is neither a subsidiary nor a joint venture. Significant influence is the power to participate in the financial and operating policy decisions of the investee but is not control or joint control over those policies. The operating results and assets and liabilities of associates are incorporated in these consolidated financial statements using the equity method of accounting. Under the equity method, an investment in an associate is initially recognized in the consolidated statements of financial position at cost and adjusted thereafter to recognize the Company’s share of profit or loss and other comprehensive income of the associate as well as the distribution received. The Company also recognizes its share in the changes in the equities of associates. Any excess of the cost of acquisition over the Company’s share of the net fair value of the identifiable assets, liabilities and contingent liabilities of an associate recognized at the date of acquisition is recognized as goodwill, which is included within the carrying amount of the investment. Any excess of the Company’s share of the net fair value of the identifiable assets, liabilities and contingent liabilities over the cost of acquisition, after reassessment, is recognized immediately in profit or loss. When necessary, the entire carrying amount of the investment (including goodwill) is tested for impairment as a single asset by comparing its recoverable amount (higher of value in use and fair value less costs to sell) with its carrying amount. Any impairment loss recognized forms part of the carrying amount of the investment. Any reversal of that impairment loss is recognized to the extent that the recoverable amount of the investment subsequently increases. When the Company subscribes to additional shares in an associate at a percentage different from its existing ownership percentage, the resulting carrying amount of the investment differs from the amount of the Company’s proportionate interest in the net assets of the associate. The Company records such a difference as an adjustment to investments with the corresponding amount charged or credited to capital surplus. If the Company’s ownership interest is reduced due to the additional subscription to the shares of associate by other investors, the proportionate amount of the gains or losses previously recognized in other comprehensive income in relation to that associate shall be reclassified to profit or loss on the same basis as would be required if the associate had directly disposed of the related assets or liabilities. When a consolidated entity transacts with an associate, profits and losses resulting from the transactions with the associate are recognized in the Company’s consolidated financial statements only to the extent of interests in the associate that are not owned by the Company. Property, Plant and Equipment Property, plant and equipment are measured at cost less accumulated depreciation and accumulated impairment. Costs include any incremental costs that are directly attributable to the construction or acquisition of the item of property, plant and equipment. Property, plant and equipment in the course of construction for production, supply or administrative purposes are carried at cost, less any recognized impairment loss. Such assets are classified to the appropriate categories of property, plant and equipment when completed and ready for intended use. Depreciation of these assets, on the same basis as other identical categories of property, plant and equipment, commences when the assets are available for their intended use. Depreciation is recognized so as to write off the cost of the assets less their residual values over their useful lives, and it is computed using the straight-line method mainly over the following estimated useful lives: land improvements—20 years; buildings (assets used by the Company and assets subject to operating leases)- 10 to 20 years; machinery and equipment (assets used by the Company and assets subject to operating leases) - 5 years; and office equipment—5 years. The estimated useful lives, residual values and depreciation method are reviewed at the end of each reporting period, with the effect of any changes in estimates accounted for on a prospective basis. Land is not depreciated. An item of property, plant and equipment is derecognized upon disposal or when no future economic benefits are expected to arise from the continued use of the assets. Any gain or loss arising on the disposal or retirement of an item of property, plant and equipment is determined as the difference between the sales proceeds and the carrying amount of the asset and is recognized in profit or loss. Leases 2018 Leases are classified as finance lease whenever the terms of the lease transfer substantially all the risks and rewards of ownership to the lessee. All other leases are classified as operating leases. The Company as lessor Rental income from operating leases is recognized on a straight-line basis over the term of the lease. The Company as lessee Operating lease payments are recognized as an expense on a straight-line basis over the lease term. 2019 and 2020 For a contract that contains a lease component and non-lease non-lease The Company as lessor Rental income from operating lease is recognized on a straight-line basis over the term of the lease. The Company as lessee Except for payments for low-value right-of-use Right-of-use right-of-use Right-of-use Right-of-use right-of-use right-of-use right-of-use Lease liabilities are measured at the present value of the lease payments. Lease payments comprise fixed payments, variable lease payments which depend on an index or a rate and the exercise price of a purchase option if the Company is reasonably certain to exercise that option. The lease payments are discounted using the lessee’s incremental borrowing rates. Subsequently, lease liabilities are measured at amortized cost using the effective interest method, with interest expense recognized over the lease terms. When there is a change in a lease term, a change in future lease payments resulting from a change in an index or a rate used to determine those payments, or a change in the assessment of an option to purchase an underlying asset, the Company remeasures the lease liabilities with a corresponding adjustment to the right-of-use Variable lease payments that do not depend on an index or a rate are recognized as expenses in the periods in which they are incurred. Intangible Assets Goodwill Goodwill arising on an acquisition of a business is carried at cost as established at the date of acquisition of the business less accumulated impairment losses, if any. Other intangible assets Other separately acquired intangible assets with finite useful lives are carried at cost less accumulated amortization and accumulated impairment losses. Amortization is recognized using the straight-line method over the following estimated useful lives: Technology license fees - the estimated life of the technology or the term of the technology transfer contract; software and system design costs - 3 years or contract period; patent and others - the economic life or contract period. The estimated useful life and amortization method are reviewed at the end of each reporting period, with the effect of any changes in estimate being accounted for on a prospective basis. Impairment of Tangible Assets, Right-of-use Goodwill Goodwill is not amortized and instead is tested for impairment annually, or more frequently when there is an indication that the cash generating unit may be impaired. For the purpose of impairment testing, goodwill is allocated to each of the Company’s cash-generating units or groups of cash-generating units that are expected to benefit from the synergies of the combination. If the recoverable amount of a cash-generating unit is less than its carrying amount, the difference is allocated first to reduce the carrying amount of any goodwill allocated to such cash generating unit and then to the other assets of the cash generating unit pro rata based on the carrying amount of each asset in the cash generating unit. Any impairment loss for goodwill is recognized directly in profit or loss. An impairment loss recognized for goodwill is not reversed in subsequent periods. Tangible assets, right-of-use At the end of each reporting period, the Company reviews the carrying amounts of its tangible assets (property, plant and equipment), right-of-use Recoverable amount is the higher of fair value less costs to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax If the recoverable amount of an asset or cash-generating unit is estimated to be less than its carrying amount, the carrying amount of the asset or cash-generating unit is reduced to its recoverable amount. An impairment loss is recognized immediately in profit or loss. When an impairment loss subsequently reverses, the carrying amount of the asset or a cash-generating unit is increased to the revised estimate of its recoverable amount, but the increased carrying amount does not exceed the carrying amount that would have been determined had no impairment loss been recognized for the asset or cash-generating unit in prior years. A reversal of an impairment loss is recognized immediately in profit or loss. Guarantee Deposit Guarantee deposit mainly consists of cash received under deposit agreements with customers to ensure they have access to the Company’s specified capacity. Cash received from customers is recorded as guarantee deposit upon receipt. Guarantee deposits are refunded to customers when terms and conditions set forth in the deposit agreements have been satisfied. Revenue Recognition The Company recognizes revenue when performance obligations are satisfied. The performance obligations are satisfied when customers obtain control of the promised goods, which is generally when the goods are delivered to the customers’ specified locations. Revenue from sale of goods is measured at the fair value of the consideration received or receivable. Revenue is reduced for estimated customer returns, rebates and other similar allowances. Estimated sales returns and other allowances is generally made and adjusted based on historical experience and the consideration of varying contractual terms to recognize refund liabilities, which is classified under accrued expenses and other current liabilities. In principle, payment term granted to customers is due 30 days from the invoice date or 30 days from the end of the month of when the invoice is issued. Due to the short term nature of the receivables from sale of goods with the immaterial discounted effect, the Company measures them at the original invoice amounts without discounting. Employee Benefits Short-term employee benefits Liabilities recognized in respect of short-term employee benefits are measured at the undiscounted amount of the benefits expected to be paid in exchange for service rendered by employees. Retirement benefits For defined contribution retirement benefit plans, payments to the benefit plan are recognized as an expense when the employees have rendered service entitling them to the contribution. For defined benefit retirement benefit plans, the cost of providing benefit is recognized based on actuarial calculations. Defined benefit costs (including service cost, net interest and remeasurement) under the defined benefit retirement benefit plans are determined using the Projected Unit Credit Method. Service cost (including current service cost), and net interest on the net defined benefit liability (asset) are recognized as employee benefits expense in the period they occur. Remeasurement, comprising actuarial gains and losses and the return on plan assets (excluding interest), is recognized in other comprehensive income in the period in which they occur. Remeasurement recognized in other comprehensive income is reflected immediately in retained earnings and will not be reclassified to profit or loss. Net defined benefit liability represents the actual deficit in the Company’s defined benefit plan. Taxation Income tax expense represents the sum of the tax currently payable and deferred tax. Current tax Income tax on unappropriated earnings (excluding earnings from foreign consolidated subsidiaries) is expensed in the year the earnings arise and adjusted to the extent that distributions are approved by the shareholders in the following year. Adjustments of prior years’ tax liabilities are added to or deducted from the current year’s tax provision. Deferred tax Deferred tax is recognized on temporary differences between the carrying amounts of assets and liabilities in the consolidated financial statements and the corresponding tax bases used in the computation of taxable profit. Deferred tax liabilities are generally recognized for all taxable temporary differences. Deferred tax assets are generally recognized for all deductible temporary differences, net operating loss carryforwards and

Critical Accounting Judgments a

Critical Accounting Judgments and Key Sources of Estimation and Uncertainty	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Critical Accounting Judgments and Key Sources of Estimation and Uncertainty	6. CRITICAL ACCOUNTING JUDGMENTS AND KEY SOURCES OF ESTIMATION AND UNCERTAINTY The Company has considered the economic implications of COVID-19 In the application of the aforementioned Company’s accounting policies, the Company is required to make judgments, estimates and assumptions about the carrying amounts of assets and liabilities that are not readily apparent from other sources. The estimates and associated assumptions are based on historical experience and other factors that are considered to be relevant. Actual results may differ from these estimates. The estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the year in which the estimate is revised if the revision affects only that year, or in the year of the revision and future years if the revision affects both current and future years. Critical Accounting Judgments Revenue Recognition The Company recognizes revenue when the conditions described in Note 5 are satisfied. Commencement of Depreciation Related to Property, Plant and Equipment Classified as Equipment under Installation and Construction in Progress (EUI/CIP) As described in Note 5, commencement of depreciation related to EUI/CIP involves determining when the assets are available for their intended use. The criteria the Company uses to determine whether EUI/CIP are available for their intended use involves subjective judgments and assumptions about the conditions necessary for the assets to be capable of operating in the intended manner. Judgments on Lease Terms In determining a lease term, the Company considers all facts and circumstances that create an economic incentive to exercise or not to exercise an option, including any expected changes in facts and circumstances from the commencement date until the exercise date of the option. Main factors considered include contractual terms and conditions covered by the optional periods, and the importance of the underlying asset to the lessee’s operations, etc. The lease term is reassessed if a significant change in circumstances that are within the control of the Company occurs. Key Sources of Estimation and Uncertainty Estimation of Sales Returns and Allowances Sales returns and other allowance is estimated and recorded based on historical experience and in consideration of different contractual terms. The amount is deducted from revenue in the same period the related revenue is recorded. The Company periodically reviews the reasonableness of the estimates. Valuation of Inventory Inventories are stated at the lower of cost or net realizable value, and the Company uses estimate to determine the net realizable value of inventory at the end of each reporting period. The Company estimates the net realizable value of inventory for normal waste, obsolescence and unmarketable items at the end of reporting period and then writes down the cost of inventories to net realizable value. The net realizable value of the inventory is determined mainly based on assumptions of future demand within a specific time horizon. Impairment of Tangible Assets, Right-of-use In the process of evaluating the potential impairment of tangible assets, right-of-use Realization of Deferred Income Tax Assets Deferred tax assets are recognized to the extent that it is probable that future taxable profits will be available against which those deferred tax assets can be utilized. Assessment of the realization of the deferred tax assets requires subjective judgment and estimate, including the future revenue growth and profitability, tax holidays, the amount of tax credits can be utilized and feasible tax planning strategies. Any changes in the global economic environment, the industry trends and relevant laws and regulations could result in significant adjustments to the deferred tax assets. Determination of Lessees’ Incremental Borrowing Rates In determining a lessee’s incremental borrowing rate used in discounting lease payments, the Company mainly takes into account the market risk-free rates, the estimated lessee’s credit spreads and secured status in a similar economic environment.

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Cash and Cash Equivalents	7. CASH AND CASH EQUIVALENTS December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Cash and deposits in banks $ 452,734.4 $ 653,580.6 Government bonds 2,188.1 3,716.1 Repurchase agreements — 1,750.4 Commercial paper 476.8 1,123.5 $ 455,399.3 $ 660,170.6 Deposits in banks consisted of highly liquid time deposits that w e

Financial Assets and Liabilitie

Financial Assets and Liabilities at Fair Value through Profit or Loss	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Financial Assets and Liabilities at Fair Value through Profit or Loss	8. FINANCIAL ASSETS AND LIABILITIES AT FAIR VALUE THROUGH PROFIT OR LOSS December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets Mandatorily measured at FVTPL Forward exchange contracts $ 162.1 $ 2,259.4 Convertible bonds 123.8 — Agency mortgage-backed securities 40.9 — $ 326.8 $ 2,259.4 Financial liabilities Held for trading Forward exchange contracts $ 982.3 $ 94.1 The Company entered into forward exchange contracts t o Outstanding forward exchange contracts consisted of the following: Maturity Date Contract Amount December 31, 2019 Sell NT$ January 2020 to June 2020 NT$108,428.0 Sell JPY January 2020 to February 2020 JPY57,471.6 Sell US$ January 2020 to March 2020 US$529.2 December 31, 2020 Sell NT$ January 2021 to March 2021 NT$144,698.0 Sell US$ January 2021 to March 2021 US$1,176.9

Financial Assets at Fair Value

Financial Assets at Fair Value Through Other Comprehensive Income	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Financial Assets at Fair Value Through Other Comprehensive Income	9. FINANCIAL ASSETS AT FAIR VALUE THROUGH OTHER COMPREHENSIVE INCOME December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Investments in debt instruments at FVTOCI Corporate bonds $ 51,790.0 $ 56,593.6 Agency bonds/Agency mortgage-backed securities 51,966.5 43,977.1 Government bonds 12,824.2 13,459.5 Asset-backed securities 10,815.9 8,368.3 127,396.6 122,398.5 Investments in equity instruments at FVTOCI Non-publicly 4,124.3 4,514.9 Publicly traded stocks — 50.0 4,124.3 4,564.9 $ 131,520.9 $ 126,963.4 Current $ 127,396.6 $ 122,448.5 Noncurrent 4,124.3 4,514.9 $ 131,520.9 $ 126,963.4 These investments in equity instruments are held for medium to long-term purposes and therefore are accounted for as FVTOCI. For dividends recognized from these investments, please refer to consolidated statements of cash flows. All the dividends are from investments held at the end of the reporting period. For the years ended December 31, 2018, 2019 and 2020, as the Company adjusted its investment portfolio or the non-publicly As of December 31, 2019 and 2020, the cumulative loss allowance for expected credit loss of NT$35.6 million and NT$32.5 million were recognized under investments in debt instruments at FVTOCI, respectively. Refer to Note 33 for information relating to the credit risk management and expected credit loss.

Financial Assets at Amortized C

Financial Assets at Amortized Cost	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Financial Assets at Amortized Cost	10. FINANCIAL ASSETS AT AMORTIZED COST December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Corporate bonds $ 7,651.7 $ 10,977.3 Less: Allowance for impairment loss (2.9 ) (7.1 ) $ 7,648.8 $ 10,970.2 Current $ 299.9 $ 6,598.0 Noncurrent 7,348.9 4,372.2 $ 7,648.8 $ 10,970.2 Refer to Note 33 for information relating to credit risk management and expected credit loss for financial assets at amortized cost.

Hedging Financial Instruments

Hedging Financial Instruments	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Hedging Financial Instruments	11. HEDGING FINANCIAL INSTRUMENTS December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets- current Fair value hedges Interest rate futures contracts $ 22.4 $ 0.1 Cash flow hedges Forward exchange contracts 3.5 — $ 25.9 $ 0.1 Financial liabilities- current Fair value hedges Interest rate futures contracts $ — $ 1.2 Cash flow hedges Forward exchange contracts 1.8 — $ 1.8 $ 1.2 Fair value hedge The Company entered into interest rate futures contracts, which are used to partially hedge against the fair value changes caused by interest rate fluctuation in the Company’s fixed income investments. The hedge ratio is adjusted in response to the changes in the financial market and capped at 100%. On the basis of economic relationships, the Company expects that the value of the interest rate futures contracts and the value of the hedged financial assets will change in opposite directions in response to movements in interest rates. The main source of hedge ineffectiveness in these hedging relationships is the credit risk of the hedged financial assets, which is not reflected in the fair value of the interest rate futures contracts. No other sources of ineffectiveness emerged from these hedging relationships during the hedging period. Amount of hedge ineffectiveness recognized in profit or loss is classified under other gains and losses. The following tables summarize the information relating to the hedges of interest rate risk. December 31, 2019 Hedging Instruments Contract Amount (US$ in Millions) Maturity Interest rate futures contracts - US Treasury bonds US$122.2 March 2020 Hedged Items Asset Carrying Amount Accumulated Amount of Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets at FVTOCI $ 7,364.7 $ (22.4) December 31, 2020 Hedging Instruments Contract Amount (US$ in Millions) Maturity Interest rate futures contracts - US Treasury bonds US$88.7 March 2021 Hedged Items Asset Carrying Amount Accumulated Amount of Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets at FVTOCI $ 6,198.7 $ 1.1 The effect for the years ended December 31, 2018, 2019 and 2020 is d e Hedging Instruments/Hedged Items Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Hedging Instruments Interest rate futures contracts - US Treasury bonds $ 11.5 $ (164.7 ) $ (353.6 ) Hedged Items Financial assets at FVTOCI (13.8 ) 177.8 353.6 $ (2.3 ) $ 13.1 $ — Cash flow hedge The Company entered into forward exchange contracts and foreign currency deposits to partially hedge foreign exchange rate risks associated with certain highly probable forecast transactions (capital expenditures). The hedge ratio is adjusted in response to the changes in the financial market and capped at 100%. The forward exchange contracts have maturities of 12 months or less. On the basis of economic relationships, the Company expects that the value of forward exchange contracts and foreign currency deposits and the value of hedged transactions will change in opposite directions in response to movements in foreign exchange rates. The main source of hedge ineffectiveness in these hedging relationships is driven by the effect of the counterparty’s own credit risk on the fair value of forward exchange contracts. No other sources of ineffectiveness emerged from these hedging relationships. For the years ended December 31, 2018, 2019 and 2020, refer to Note 23(d) for gain or loss arising from changes in the fair value of hedging instruments and the amount transferred to initial carrying amount of hedged items. The following tables summarize the information relating to the hedges for foreign currency risk. December 31, 2019 Hedging Instruments Contract Amount (In Millions) Maturity Balance in Other Equity NT$ (In Millions) Forward exchange contracts Sell NT$ 1,342.4 January 2020 $ (3.8 ) The effect for the years ended December 31, 2018, 2019 an d Hedging Instruments/Hedged Items Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Hedging Instruments Forward exchange contracts $ 34.6 $ (109.6 ) $ 24.1 Foreign currency deposits 6.4 — — $ 41.0 $ (109.6 ) $ 24.1 Hedged Items Forecast transaction (capital expenditures) $ (41.0 ) $ 109.6 $ (24.1 )

Notes and Accounts Receivable,

Notes and Accounts Receivable, Net	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Notes and Accounts Receivable, Net	12. NOTES AND ACCOUNTS RECEIVABLE, NET December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) At amortized cost Notes and accounts receivable $ 135,978.0 $ 142,771.6 Less: Loss allowance (325.3 ) (246.6 ) 135,652.7 142,525.0 At FVTOCI 3,255.9 2,955.3 $ 138,908.6 $ 145,480.3 The Company signed a contract with the bank to sell certain accounts receivable without recourse and transaction cost required. These accounts receivable are classified as at FVTOCI because they are held within a business model whose objective is achieved by both collecting contractual cash flows and selling financial assets. In principle, the payment term granted to customers is due 30 days from the invoice date or 30 days from the end of the month when the invoice is issued. Aside from recognizing impairment loss for credit-impaired accounts receivable, the Company recognizes loss allowance based on the expected credit loss ratio of customers by different risk levels with consideration of factors of historical loss ratios and customers’ financial conditions, competitiveness and business outlook. For accounts receivable past due over 90 days without collaterals or guarantees, the Company recognizes loss allowance at full amount. Aging analysis of notes and accounts receivable December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Not past due $ 126,134.8 $ 140,933.6 Past due Past due within 30 days 13,082.1 4,784.4 Past due 31-60 12.8 8.7 Past due 61-120 1.0 0.1 Past due over 121 days 3.2 0.1 Less: Loss allowance (325.3 ) (246.6 ) $ 138,908.6 $ 145,480.3 All of the Company’s accounts receivable classified as at FVTOCI w Movements of the loss allowance for accounts receivable Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 227.0 $ 7.3 $ 325.3 Provision (Reversal) (219.7 ) 318.2 (78.5 ) Effect of exchange rate changes — (0.2 ) (0.2 ) Balance, end of year $ 7.3 $ 325.3 $ 246.6 For the years ended December 31, 2018, 2019 and 2020, the changes in loss allowance were mainly due to the variations in the expected credit loss ratios and the balance of accounts receivable of different risk levels.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Inventories	13. INVENTORIES December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Finished goods $ 8,924.5 $ 21,705.6 Work in process 51,969.1 91,672.9 Raw materials 16,552.3 14,716.0 Supplies and spare parts 5,535.3 9,258.9 $ 82,981.2 $ 137,353.4 Write-down of inventories to net realizable v a Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Inventory losses (reversal of write-down of inventories) $ 1,259.5 $ (1,983.0 ) $ 3,664.5 The aforementioned inventory losses (reversal of write-down of inventories) for the years ended December 31, 2018 and 2019 excluded computer virus outbreak losses and wafer contamination losses. Please refer to related losses in Note 37.

Investments Accounted for Using

Investments Accounted for Using Equity Method	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Investments Accounted for Using Equity Method	14. INVESTMENTS ACCOUNTED FOR USING EQUITY METHOD Associates consisted of the following: Place of Incorporation and Operation Carrying Amount % of Ownership and Voting Rights Name of Associate Principal Activities December 31, December 31, December 31, December 31, NT$ NT$ (In Millions) (In Millions) Vanguard International Semiconductor Corporation (VIS) Manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing and design service of masks Hsinchu, Taiwan $ 8,960.5 $ 8,964.1 28% 28% Systems on Silicon Manufacturing Company Pte Ltd. (SSMC) Manufacturing and selling of integrated circuits and other semiconductor devices Singapore 6,502.2 5,900.2 39% 39% Xintec Inc. (Xintec) Wafer level chip size packaging and wafer level post passivation interconnection service Taoyuan, Taiwan 1,842.8 2,522.3 41% 41% Global Unichip Corporation (GUC) Researching, developing, manufacturing, testing and marketing of integrated circuits Hsinchu, Taiwan 1,274.8 1,315.4 35% 35% Mutual-Pak Manufacturing of electronic parts, wholesaling and retailing of electronic materials, and researching, developing and testing of RFID New Taipei, Taiwan 38.5 28.2 28% 28% $ 18,618.8 $ 18,730.2 As of December 31, 2019 and 2020, no investments in associates are individually material to the Company. Please refer to the consolidated statements of profit or loss and other comprehensive income for recognition of share of both profit (loss) and other comprehensive income (loss) of associates that are not individually material. The market prices of the investments accounted for using the equity method in publicly traded stocks calculated by the closing price at the end of the reporting period are summarized as follows. The closing price represents the quoted price in active markets, the level 1 fair value measure m December 31, 2019 December 31, 2020 NT$ NT$ Name of Associate (In Millions) (In Millions) VIS $ 36,812.9 $ 53,849.9 Xintec $ 8,958.2 $ 20,420.2 GUC $ 11,251.8 $ 15,827.2

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Property, Plant and Equipment	15. PROPERTY, PLANT AND EQUIPMENT 2018 Land and Land Buildings Machinery and Office Equipment Equipment under Total NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2018 $ 3,983.2 $ 379,134.6 $ 2,487,752.3 $ 42,391.5 $ 167,353.5 $ 3,080,615.1 Additions — 40,396.4 247,042.3 6,773.4 5,812.3 300,024.4 Disposals or retirements — (410.9 ) (5,972.5 ) (790.8 ) — (7,174.2 ) Effect of exchange rate changes 28.2 (405.8 ) (61.9 ) 8.1 (254.8 ) (686.2 ) Balance at December 31, 2018 $ 4,011.4 $ 418,714.3 $ 2,728,760.2 $ 48,382.2 $ 172,911.0 $ 3,372,779.1 Accumulated depreciation and impairment Balance at January 1, 2018 $ 510.5 $ 194,446.5 $ 1,795,448.9 $ 27,666.9 $ — $ 2,018,072.8 Additions 20.9 24,293.4 258,195.3 5,615.3 — 288,124.9 Disposals or retirements — (399.0 ) (4,773.6 ) (790.0 ) — (5,962.6 ) Impairment — — 423.5 — — 423.5 Effect of exchange rate changes 19.2 33.2 (15.1 ) 32.9 — 70.2 Balance at December 31, 2018 $ 550.6 $ 218,374.1 $ 2,049,279.0 $ 32,525.1 $ — $ 2,300,728.8 Carrying amounts at December 31, 2018 $ 3,460.8 $ 200,340.2 $ 679,481.2 $ 15,857.1 $ 172,911.0 $ 1,072,050.3 The significant part of the Company’s buildings includes main plants, mechanical and electrical power equipment and clean rooms, and the related depreciation is calculated using the estimated useful lives of 20 years, 10 years and 10 years, respectively. For the year ended December 31, 2018, the Company recognized an impairment loss of NT$423.5 million for certain machinery and equipment that was assessed to have no future use, and the recoverable amount of certain machinery and equipment was nil. Such impairment loss was recognized in other operating income and expenses. 2019 and 2020 December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Assets used by the Company $ 1,352,313.9 $ 1,554,585.9 Assets subject to operating leases 63.5 1,003.2 $ 1,352,377.4 $ 1,555,589.1 a. Assets used by the Company Land and Land Buildings Machinery and Office Equipment Equipment under Total NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Cost Balance at January 1, 2019 $ 4,011.4 $ 418,151.7 $ 2,728,760.2 $ 48,382.2 $ 172,911.0 $ 3,372,216.5 Additions — 21,448.5 179,798.4 7,415.0 355,621.1 564,283.0 Disposals or retirements — (159.0 ) (17,381.6 ) (1,043.3 ) — (18,583.9 ) Transfers from right-of-use — — 619.8 — — 619.8 Effect of disposal of subsidiary — — — (0.5 ) — (0.5 ) Effect of exchange rate changes (19.6 ) (1,366.2 ) (5,173.8 ) (142.0 ) (237.0 ) (6,938.6 ) Balance at December 31, 2019 $ 3,991.8 $ 438,075.0 $ 2,886,623.0 $ 54,611.4 $ 528,295.1 $ 3,911,596.3 Accumulated depreciation and impairment Balance at January 1, 2019 $ 550.6 $ 217,899.2 $ 2,049,279.0 $ 32,525.1 $ — $ 2,300,253.9 Additions 1.6 26,026.6 246,724.2 6,012.5 — 278,764.9 Disposals or retirements — (144.4 ) (12,880.8 ) (1,042.1 ) — (14,067.3 ) Transfers from right-of-use — — 20.7 — — 20.7 Reversal of impairment — — (301.4 ) — — (301.4 ) Effect of disposal of subsidiary — — — (0.5 ) — (0.5 ) Effect of exchange rate changes (13.5 ) (722.1 ) (4,575.7 ) (76.6 ) — (5,387.9 ) Balance at December 31, 2019 $ 538.7 $ 243,059.3 $ 2,278,266.0 $ 37,418.4 $ — $ 2,559,282.4 Carrying amounts at December 31, 2019 $ 3,453.1 $ 195,015.7 $ 608,357.0 $ 17,193.0 $ 528,295.1 $ 1,352,313.9 Cost Balance at January 1, 2020 $ 3,991.8 $ 438,075.0 $ 2,886,623.0 $ 54,611.4 $ 528,295.1 $ 3,911,596.3 Additions (deductions) — 84,882.5 729,943.3 15,112.9 (304,218.0 ) 525,720.7 Disposals or retirements — (41.5 ) (6,397.3 ) (734.1 ) — (7,172.9 ) Transfers from assets subject to operating leases — 23.1 — — — 23.1 Transfers to assets subject to operating leases — — (1,199.0 ) — — (1,199.0 ) Effect of exchange rate changes (49.2 ) (491.7 ) (1,964.3 ) (127.5 ) (111.7 ) (2,744.4 ) Balance at December 31, 2020 $ 3,942.6 $ 522,447.4 $ 3,607,005.7 $ 68,862.7 $ 223,965.4 $ 4,426,223.8 Accumulated depreciation and impairment Balance at January 1, 2020 $ 538.7 $ 243,059.3 $ 2,278,266.0 $ 37,418.4 $ — $ 2,559,282.4 Additions 1.5 29,209.1 285,393.6 7,216.9 — 321,821.1 Disposals or retirements — (27.9 ) (6,012.9 ) (732.4 ) — (6,773.2 ) Transfers from assets subject to operating leases — 8.2 — — — 8.2 Transfers to assets subject to operating leases — — (202.6 ) — — (202.6 ) Impairment — — 10.2 — — 10.2 Effect of exchange rate changes (34.1 ) (449.2 ) (1,924.3 ) (100.6 ) — (2,508.2 ) Balance at December 31, 2020 $ 506.1 $ 271,799.5 $ 2,555,530.0 $ 43,802.3 $ — $ 2,871,637.9 Carrying amounts at December 31, 2020 $ 3,436.5 $ 250,647.9 $ 1,051,475.7 $ 25,060.4 $ 223,965.4 $ 1,554,585.9 The significant part of the Company’s buildings includes main plants, mechanical and electrical power equipment and clean rooms, and the related depreciation is calculated using the estimated useful lives of 20 years, 10 years and 10 years, respectively. In the first quarter of 2019, the Company recognized a reversal of impairment loss of NT$301.4 million due to redeployment of certain idle machinery and equipment. Such reversal of impairment loss was recognized in other operating income and expenses. b. Assets subject to operating leases Buildings Machinery and Total NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2019 $ 562.6 $ — $ 562.6 Balance at December 31, 2019 $ 562.6 $ — $ 562.6 Accumulated depreciation Balance at January 1, 2019 $ 474.9 $ — $ 474.9 Additions 24.2 — 24.2 Balance at December 31, 2019 $ 499.1 $ — $ 499.1 Carrying amounts at December 31, 2019 $ 63.5 $ — $ 63.5 Cost Balance at January 1, 2020 $ 562.6 $ — $ 562.6 Disposals or retirements (311.9 ) — (311.9 ) Transfers to assets used by the Company (23.1 ) — (23.1 ) Transfers from assets used by the Company — 1,199.0 1,199.0 Balance at December 31, 2020 $ 227.6 $ 1,199.0 $ 1,426.6 Accumulated depreciation Balance at January 1, 2020 $ 499.1 $ — $ 499.1 Additions 16.3 19.4 35.7 Disposals or retirements (305.8 ) — (305.8 ) Transfers to assets used by the Company (8.2 ) — (8.2 ) Transfers from assets used by the Company — 202.6 202.6 Balance at December 31, 2020 $ 201.4 $ 222.0 $ 423.4 Carrying amounts at December 31, 2020 $ 26.2 $ 977.0 $ 1,003.2 Operating leases relate to leases of buildings and leases of machinery and equipment with lease terms approximately between 1 to 5 years. The lessees do not have purchase options to acquire the assets at the expiry of the lease periods. The maturity ana l December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Year 1 $ 18.4 $ 149.1 Year 2 17.0 17.0 Year 3 17.0 — $ 52.4 $ 166.1

Lease Arrangements

Lease Arrangements	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Lease Arrangements	16. LEASE ARRANGEMENTS 2018 The Company’s ma j The Company expensed the lease payments as follows: Year Ended NT$ (In Millions) Minimum lease payments $ 4,243.1 Future minimum lease payments under the above non-cancellable December 31, NT$ (In Millions) Not later than 1 year $ 5,824.1 Later than 1 year and not later than 5 years 5,834.9 Later than 5 years 9,190.6 $ 20,849.6 2019 and 2020 a. Right-of-use December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Carrying amounts Land $ 14,064.0 $ 25,141.9 Buildings 2,351.8 2,544.8 Machinery and equipment 775.8 — Office equipment 40.8 41.8 $ 17,232.4 $ 27,728.5 Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Additions to right-of-use $ 1,033.0 $ 13,481.2 Depreciation of right-of-use Land $ 957.1 $ 1,312.9 Buildings 458.8 569.5 Machinery and equipment 1,184.4 775.8 Office equipment 22.4 23.4 $ 2,622.7 $ 2,681.6 Income from subleasing right-of-use $ 55.0 $ 79.6 b. Lease liabilities December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Carrying amounts Current portion (classified under accrued expenses and other current liabilities) $ 2,275.1 $ 1,828.0 Noncurrent portion 15,041.8 20,560.6 $ 17,316.9 $ 22,388.6 Ranges of discount rates for lease liabilities are as follows: December 31, 2019 December 31, 2020 Land 0.67%-2.14% 0.48%-2.14% Buildings 0.67%-3.88% 0.54%-3.88% Machinery and equipment 3.24% — Office equipment 0.64%-3.88% 0.28%-3.88% c.   Material terms of right-of-use The Company leases land and buildings mainly for the use of plants and offices with lease terms of 1 to 36 years. The lease contracts for land located in the R.O.C. specify that lease payments will be adjusted every 2 years on the basis of changes in announced land value prices. The Company does not have purchase options to acquire the leasehold land and buildings at the end of the lease terms. The Company leases machinery and equipment for use in operation with lease terms of 2 years. The Company has purchase options to acquire leasehold machinery and equipment at the end of the lease terms. As of September 30, 2020, the aforementioned lease contract has been expired. d.  Subleases The Company subleases the right to use its buildings and machinery and equipment under operating leases with lease terms of 1 to 6 years. The maturity analysis of lease payments receivable under operating subleases is as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Year 1 $ 58.6 $ 144.1 Year 2 1.9 — $ 60.5 $ 144.1 e.   Other lease information Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Expenses relating to short-term leases $ 5,007.1 $ 3,153.5 Expenses relating to low-value $ 0.5 $ 0.3 Expenses relating to variable lease payments not included in the measurement of lease liabilities $ 195.1 $ 257.0 Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Total cash outflow for leases $ 7,724.4 $ 6,354.6

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Intangible Assets	17. INTANGIBLE ASSETS Goodwill Technology Software and Patent and Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2018 $ 5,648.7 $ 10,443.3 $ 25,186.3 $ 5,716.0 $ 46,994.3 Additions — 533.7 4,601.9 1,969.4 7,105.0 Disposals or retirements — — (186.7 ) (31.2 ) (217.9 ) Effect of exchange rate changes 146.8 (2.5 ) (6.9 ) 2.1 139.5 Balance at December 31, 2018 $ 5,795.5 $ 10,974.5 $ 29,594.6 $ 7,656.3 $ 54,020.9 Accumulated amortization and impairment Balance at January 1, 2018 $ — $ 7,694.9 $ 20,376.7 $ 4,747.5 $ 32,819.1 Additions — 1,063.6 2,835.3 522.5 4,421.4 Disposals or retirements — — (186.6 ) (31.2 ) (217.8 ) Effect of exchange rate changes — (2.5 ) (1.7 ) 0.3 (3.9 ) Balance at December 31, 2018 $ — $ 8,756.0 $ 23,023.7 $ 5,239.1 $ 37,018.8 Carrying amounts at December 31, 2018 $ 5,795.5 $ 2,218.5 $ 6,570.9 $ 2,417.2 $ 17,002.1 Cost Balance at January 1, 2019 $ 5,795.5 $ 10,974.5 $ 29,594.6 $ 7,656.3 $ 54,020.9 Additions — 4,879.6 3,710.4 647.8 9,237.8 Disposals or retirements — — (260.9 ) — (260.9 ) Effect of exchange rate changes (102.1 ) 0.9 (20.1 ) (1.2 ) (122.5 ) Balance at December 31, 2019 $ 5,693.4 $ 15,855.0 $ 33,024.0 $ 8,302.9 $ 62,875.3 Accumulated amortization and impairment Balance at January 1, 2019 $ — $ 8,756.0 $ 23,023.7 $ 5,239.1 $ 37,018.8 Additions — 1,066.9 3,747.3 658.2 5,472.4 Disposals or retirements — — (258.6 ) — (258.6 ) Effect of exchange rate changes — 0.9 (10.3 ) (0.9 ) (10.3 ) Balance at December 31, 2019 $ — $ 9,823.8 $ 26,502.1 $ 5,896.4 $ 42,222.3 Carrying amounts at December 31, 2019 $ 5,693.4 $ 6,031.2 $ 6,521.9 $ 2,406.5 $ 20,653.0 Cost Balance at January 1, 2020 $ 5,693.4 $ 15,855.0 $ 33,024.0 $ 8,302.9 $ 62,875.3 Additions — 6,308.9 3,275.8 2,974.8 12,559.5 Disposals or retirements — — (60.5 ) — (60.5 ) Effect of exchange rate changes (256.8 ) (2.2 ) (0.3 ) (0.1 ) (259.4 ) Balance at December 31, 2020 $ 5,436.6 $ 22,161.7 $ 36,239.0 $ 11,277.6 $ 75,114.9 Accumulated amortization and impairment Balance at January 1, 2020 $ — $ 9,823.8 $ 26,502.1 $ 5,896.4 $ 42,222.3 Additions — 2,404.5 3,669.2 1,112.5 7,186.2 Disposals or retirements — — (59.9 ) — (59.9 ) Effect of exchange rate changes — (2.1 ) 0.3 — (1.8 ) Balance at December 31, 2020 $ — $ 12,226.2 $ 30,111.7 $ 7,008.9 $ 49,346.8 Carrying amounts at December 31, 2020 $ 5,436.6 $ 9,935.5 $ 6,127.3 $ 4,268.7 $ 25,768.1 The Company’s goodwill has been tested for impairment at the end of the annual reporting period and the recoverable amount is determined based on the value in use. The value in use was calculated based on the cash flow forecast from the financial budgets covering the future five-year period, and the Company used annual discount rates of 8.0% in both years in its test of impairment as of December 31, 2019 and 2020, to reflect the relevant specific risk in the cash-generating unit. For the years ended December 31, 2018, 2019 and 2020, the Company did not recognize any impairment loss on goodwill.

Loans and Bonds Payable

Loans and Bonds Payable	12 Months Ended
	Dec. 31, 2020
Short-term loans [member]
Statement [LineItems]
Loans and Bonds Payable	18. SHORT-TERM LOANS December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Unsecured loans Amount $ 118,522.3 $ 88,559.0 Loan content US$ (in millions) $ 2,370.0 $ 200.0 EUR (in millions) 1,410.0 2,398.0 Annual i 0.01%-2.22 % (0.54)%-0.33 % Maturity date Due by May 2020 Due by February
Bonds payable [member]
Statement [LineItems]
Loans and Bonds Payable	19. BONDS PAYABLE December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Domestic unsecured bonds $ 56,900.0 $ 173,197.0 Overseas unsecured bonds — 84,291.0 Less: Discounts on bonds payable — (782.9 ) Less: Current portion (31,800.0 ) (2,600.0 ) $ 25,100.0 $ 254,105.1 The major terms of domestic unsecured bonds are as follows: Issuance Tranche Issuance Period Total Amount Coupon Repayment and NT$ unsecured bonds 100-2 B January 2012 to January 2019 $ 7,000.0 1.46 % Bullet repayment; interest payable annually 101-1 B August 2012 to August 2019 9,000.0 1.40 % The same as above Issuance Tranche Issuance Period Total Amount Coupon Repayment and 101-2 B September 2012 to September 2019 $ 9,000.0 1.39 % Bullet repayment; interest payable annually 101-3 — October 2012 to October 2022 4,400.0 1.53 % The same as above 101-4 B January 2013 to January 2020 10,000.0 1.35 % The same as above C January 2013 to January 2023 3,000.0 1.49 % The same as above 102-1 B February 2013 to February 2020 11,600.0 1.38 % The same as above C February 2013 to February 2023 3,600.0 1.50 % The same as above 102-2 A July 2013 to July 2020 10,200.0 1.50 % The same as above B July 2013 to July 2023 3,500.0 1.70 % The same as above 102-3 B August 2013 to August 2019 8,500.0 1.52 % The same as above 102-4 C September 2013 to March 2019 1,400.0 1.60 % Bullet repayment; interest payable annually (interest for the six months prior to maturity will accrue on the basis of actual days and be repayable at maturity) D September 2013 to March 2021 2,600.0 1.85 % The same as above E September 2013 to March 2023 5,400.0 2.05 % The same as above F September 2013 to September 2023 2,600.0 2.10 % Bullet repayment; interest payable annually 109-1 A March 2020 to March 2025 3,000.0 0.58 % The same as above B March 2020 to March 2027 10,500.0 0.62 % The same as above C March 2020 to March 2030 10,500.0 0.64 % The same as above 109-2 A April 2020 to April 2025 5,900.0 0.52 % The same as above B April 2020 to April 2027 10,400.0 0.58 % The same as above C April 2020 to April 2030 5,300.0 0.60 % The same as above 109-3 A May 2020 to May 2025 4,500.0 0.55 % The same as above B May 2020 to May 2027 7,500.0 0.60 % The same as above Issuance Tranche Issuance Period Total Amount Coupon Repayment and 109-3 C May 2020 to May 2030 $ 2,400.0 0.64 % Bullet repayment; interest payable annually 109-4 A July 2020 to July 2025 5,700.0 0.58 % Two equal installments in last two years; interest payable annually B July 2020 to July 2027 6,300.0 0.65 % The same as above C July 2020 to July 2030 1,900.0 0.67 % The same as above 109-5 A September 2020 to September 2025 4,800.0 0.50 % The same as above B September 2020 to September 2027 8,000.0 0.58 % The same as above C September 2020 to September 2030 2,800.0 0.60 % The same as above 109-6 (green bond) A December 2020 to December 2025 1,600.0 0.40 % The same as above B December 2020 to December 2027 5,600.0 0.44 % The same as above C December 2020 to December 2030 4,800.0 0.48 % The same as above 109-7 A December 2020 to December 2025 1,900.0 0.36 % The same as above B December 2020 to December 2027 10,200.0 0.41 % The same as above C December 2020 to December 2030 6,400.0 0.45 % The same as above (Concluded) Issuance Tranche Issuance Period Total Amount Coupon Repayment and Interest Payment US$ unsecured bonds 109-1 — September 2020 to September 2060 US$ 1,000.0 2.70 % Bullet repayment (callable on the 5th anniversary of the issue date and every anniversary thereafter); interest payable annually The major terms of overseas unsecured bonds are as follows: Issuance Period Total Amount (In Millions) Coupon Repayment and Interest Payment September 2020 to September 2025 US$ 1,000.0 0.75% Bullet repayment (callable at any time, in whole or in part, at the relevant redemption price according to relevant agreements); interest payable semi-annually September 2020 to September 2027 750.0 1.00% The same as above September 2020 to September 2030 1,250.0 1.375% The same as above
Long-term bank loans [member]
Statement [LineItems]
Loans and Bonds Payable	20. LONG-TERM BANK LOANS December 31, 2020 NT$ (In Millions) Unsecured loans $ 2,000.0 Less: Discounts on government grants (32.4 ) $ 1,967.6 Loan content Annual interest rate 0.4% Maturity date Due by September The long-term bank loans of the Company are with preferential interest rates subsidized by the government, and the loan proceeds are used to fund qualifying capital expenditure.

Retirement Benefit Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Retirement Benefit Plans	21. RETIREMENT BENEFIT PLANS a. Defined contribution plans The plan under the R.O.C. Labor Pension Act (the “Act”) is deemed a defined contribution plan. Pursuant to the Act, TSMC and VisEra Tech have made monthly contributions equal to 6% of each employee’s monthly salary to employees’ pension accounts. Furthermore, TSMC North America, TSMC China, TSMC Nanjing, TSMC Europe, TSMC Canada and TSMC Technology also make monthly contributions at certain percentages of the basic salary of their employees. Accordingly, the Company recognized expenses of NT$2,568.9 million, NT$2,609.7 million and NT$2,809.5 million for the years ended December 31, 2018, 2019 and 2020, respectively. b. Defined benefit plans TSMC has defined benefit plans under the R.O.C. Labor Standards Law that provide benefits based on an employee’s length of service and average monthly salary for the six-month Amounts recognized in respect of these defined benefit plans were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Current service cost $ 137.7 $ 135.6 $ 123.3 Net interest expense 144.1 124.0 81.6 Components of defined benefit costs recognized in profit or loss 281.8 259.6 204.9 Remeasurement on the net defined benefit liability: Return on plan assets (excluding amounts included in net interest expense) (71.3 ) (124.4 ) (139.2 ) Actuarial loss (gain) arising from experience adjustments 334.7 (438.0 ) 494.1 Actuarial gain arising from changes in demographic assumptions — (233.2 ) — Actuarial loss arising from changes in financial assumptions 597.8 541.7 3,161.9 Components of defined benefit costs recognized in other comprehensive income 861.2 (253.9 ) 3,516.8 Total $ 1,143.0 $ 5.7 $ 3,721.7 The pension costs of the aforementioned defined benefit plans were recognized in profit or loss by the following categories: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Cost of revenue $ 177.8 $ 157.8 $ 126.3 Research and development expenses 79.1 72.7 57.3 General and administrative expenses 20.6 25.1 18.2 Marketing expenses 4.3 4.0 3.1 $ 281.8 $ 259.6 $ 204.9 The amounts arising from the defined benefit obligation of the Company were as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Present value of defined benefit obligation $ 13,484.1 $ 16,980.3 Fair value of plan assets (4,301.6 ) (5,066.2 ) Net defined benefit liability $ 9,182.5 $ 11,914.1 Movements in the present value of the defined benefit obligation were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 12,774.6 $ 13,662.7 $ 13,484.1 Current service cost 137.7 135.6 123.3 Interest expense 207.8 175.4 118.8 Remeasurement: Actuarial loss (gain) arising from experience adjustments 334.7 (438.0 ) 494.1 Actuarial gain arising from changes in demographic assumptions — (233.2 ) — Actuarial loss arising from changes in financial assumptions 597.8 541.7 3,161.9 Benefits paid from plan assets (274.3 ) (344.1 ) (399.0 ) Benefits paid directly by the Company (115.6 ) (16.0 ) (2.9 ) Balance, end of year $ 13,662.7 $ 13,484.1 $ 16,980.3 Movements in the fair value of the plan assets were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 3,923.9 $ 4,011.3 $ 4,301.6 Interest income 63.7 51.4 37.2 Remeasurement: Return on plan assets (excluding amounts included in net interest expense) 71.3 124.4 139.2 Contributions from employer 226.7 458.6 987.2 Benefits paid from plan assets (274.3 ) (344.1 ) (399.0 ) Balance, end of year $ 4,011.3 $ 4,301.6 $ 5,066.2 The fair value of the plan assets by major categories at the end of reporting period was as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Cash $ 713.2 $ 632.8 Equity instruments 2,313.8 2,926.7 Debt instruments 1,274.6 1,506.7 $ 4,301.6 $ 5,066.2 The actuarial valuations of the present value of the defined benefit obligation were carried out by qualified actuaries. The principal assumptions of the actuarial valuation were as follows: Measurement Date December 31, 2019 December 31, 2020 Discount rate 0.90% 0.40% Future salary increase rate 3.00% 3.00% (Note) Note: The Company has an additional 20 percent pay raise in 2021. Through the defined benefit plans under the R.O.C. Labor Standards Law, the Company is exposed to the following risks: 1) Investment risk: The pension funds are invested in equity and debt securities, bank deposits, etc. The investment is conducted at the discretion of the government’s designated authorities or under the mandated management. However, under the R.O.C. Labor Standards Law, the rate of return on assets shall not be less than the average interest rate on a two-year 2) Interest risk: A decrease in the government bond interest rate will increase the present value of the defined benefit obligation; however, this will be partially offset by an increase in the return on the debt investments of the plan assets. Assuming a hypothetical decrease in interest rate at the end of the reporting period contributed to a decrease of 0.5% (and not below 0.0%) in the discount rate and all other assumptions were held constant, the present value of the defined benefit obligation would increase by NT$725.0 million and NT$694.7 million as of December 31, 2019 and 2020, respectively. 3) Salary risk: The present value of the defined benefit obligation is calculated by reference to the future salaries of plan participants. As such, an increase in the salary of the plan participants will increase the present value of the defined benefit obligation. Assuming the expected salary rate increases by 0.5% at t h The sensitivity analysis presented above may not be representative of the actual change in the defined benefit obligation as it is unlikely that the change in assumptions would occur in isolation of one another as some of the assumptions may be correlated. Furthermore, in presenting the above sensitivity analysis, the present value of the defined benefit obligation has been calculated using the projected unit credit method at the end of the reporting period, which is the same as that applied in calculating the defined benefit obligation liability. The Company expects to make contributions of NT$229.9 million to the defined benefit plans in the next year starting from December 31, 2020. The weighted average duration of the defined benefit obligation is 9 years.

Guarantee Deposits

Guarantee Deposits	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Guarantee Deposits	22. GUARANTEE DEPOSITS December 31, December 31, NT$ NT$ (In Millions) (In Millions) Capacity guarantee $ 1,499.4 $ — Others 230.5 350.0 $ 1,729.9 $ 350.0 Current portion (classified under accrued expenses and other current liabilities) $ 1,553.0 $ 84.4 Noncurrent portion 176.9 265.6 $ 1,729.9 $ 350.0 Some of guarantee deposits were refunded to customers by offsetting related accounts rec e

Equity

Equity	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Equity	23. EQUITY a. Capital stock December 31, December 31, NT$ NT$ (In Millions) (In Millions) Authorized shares 28,050.0 28,050.0 Authorized capital $ 280,500.0 $ 280,500.0 Issued and paid shares 25,930.3 25,930.3 Issued capital $ 259,303.8 $ 259,303.8 A holder of issued common shares with par value of NT$10 per share is entitled to vote and to receive dividends. The authorized shares include 500.0 million shares allocated for the exercise of employee stock options. As of December 31, 2020, 1,064.4 million ADSs of TSMC were traded on the NYSE. The number of common shares represented by the ADSs was 5,321.8 million shares (one ADS represents five common shares). b. Capital surplus December 31, December 31, NT$ NT$ (In Millions) (In Millions) Additional paid-in $ 24,185.0 $ 24,185.0 From merger 22,804.5 22,804.5 From convertible bonds 8,892.9 8,892.9 From share of changes in equities of subsidiaries 121.8 121.8 From share of changes in equities of associates 302.2 302.5 Donations 33.3 40.5 $ 56,339.7 $ 56,347.2 Under the R.O.C. relevant laws, the capital surplus generated from donations and the excess of the issuance price over the par value of capital stock (including the stock issued for new capital, mergers and convertible bonds) may be used to offset a deficit; in addition, when the Company has no deficit, such capital surplus may be distributed as cash dividends or stock dividends up to a certain percentage of TSMC’s paid-in . c. Retained earnings and dividend policy The amendments to TSMC’s Articles of Incorporation had been approved by TSMC’s shareholders in its meeting held on June 5, 2019, which stipulate that earnings distribution may be made on a quarterly basis after the close of each quarter. Distribution of earnings by way of cash dividends should be approved by TSMC’s Board of Directors and reported to TSMC’s shareholders in its meeting. TSMC’s amended Articles of Incorporation provide that, when allocating earnings, TSMC shall first estimate and reserve the taxes to be paid, offset its losses, set aside a legal capital reserve at 10% of the remaining earnings (until the accumulated legal capital reserve equals TSMC’s paid-in TSMC’s Articles of Incorporation also provide that profits of TSMC may be distributed by way of cash dividend and/or stock dividend. However, distribution of earnings shall be made preferably by way of cash dividend. Distribution of earnings may also be made by way of stock dividend, provided that the ratio for stock dividend shall not exceed 50% of the total distribution. The reserve may be used to offset a deficit, or be distributed as dividends in cash or stocks for the portion in excess of 25% of the paid-in Pursuant to existing regulations, the Company is required to set aside additional special capital reserve equivalent to the net debit balance of the other components of stockholders’ equity, such as the accumulated balance of foreign currency translation reserve, unrealized valuation gain or loss from fair value through other comprehensive inco m The appropriation of 2018 earnings has been approved by TSMC’s shareholders in its meeting held on June 5, 2019. The appropriation and cash dividends per share were as follows: Appropriation of Earnings Cash Dividends Per Share NT$ (NT$) (In Millions) Legal capital reserve $ 35,113.1 Special capital reserve $ (11,459.5 ) Cash dividends to shareholders $ 207,443.0 $ 8.0 The appropriations of 2019 and 2020 quarterly earnings have been approved by TSMC’s Board of Directors in its meeting, respectively. The appropriations and cash dividends per share were as follows: First Quarter Second Quarter Third Quarter Fourth Quarter NT$ NT$ NT$ NT$ Resolution date of TSMC’s Board of Directors in its meeting June 5, 2019 August 13, 2019 November 12, February 11, Special capital reserve $ (4,724.0 ) $ (3,338.2 ) $ 3,289.2 $ 16,893.0 Cash dividends to shareholders $ 51,860.8 $ 64,826.0 $ 64,826.0 $ 64,826.0 Cash dividends per share (NT$) $ 2.0 $ 2.5 $ 2.5 $ 2.5 First Quarter Second Quarter Third Quarter Fourth Quarter NT$ NT$ NT$ NT$ Resolution date of TSMC’s Board of Directors in its meeting May 12, 2020 August 11, 2020 November 10, February Special capital reserve $ (2,694.8 ) $ 11,884.5 $ 5,501.3 $ 12,420.7 Cash dividends to shareholders $ 64,826.0 $ 64,826.0 $ 64,826.0 $ 64,826.0 Cash dividends per share (NT$) $ 2.5 $ 2.5 $ 2.5 $ 2.5 The special capital reserve for 2020 is to be presented for approval in the TSMC’s shareholders’ meeting to be held on June 8, 2021 (expected). d. Others Changes in others were as follows: Year Ended December 31, 2018 Foreign Unrealized Gain (Loss) on Unearned Total NT$ (In Millions) NT$ NT$ NT$ NT$ Balance, beginning of year(IFRS 9) $ (26,697.7 ) $ (524.9 ) $ 4.2 $ (10.3 ) $ (27,228.7 ) Exchange differences arising on translation of foreign operations 14,562.0 — — — 14,562.0 Year Ended December 31, 2018 Foreign Unrealized Gain (Loss) on Unearned Total NT$ (In Millions) NT$ NT$ NT$ NT$ Unrealized gain (loss) on financial assets at FVTOCI Equity instruments $ — $ (3,311.6 ) $ — $ — $ (3,311.6 ) Debt instruments — (1,858.0 ) — — (1,858.0 ) Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — 1,193.1 — — 1,193.1 Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — 989.1 — — 989.1 Loss allowance adjustments from debt instruments — (2.0 ) — — (2.0 ) Gain (loss) arising on changes in the fair value of hedging instruments — — 41.0 — 41.0 Transferred to initial carrying amount of hedged items — — (22.2 ) — (22.2 ) Share of other comprehensive income (loss) of associates 93.3 (6.8 ) — — 86.5 Share of unearned stock-based employee compensation of associates — — — 8.5 8.5 Income tax effect — 91.8 0.6 — 92.4 Balance, end of year $ (12,042.4 ) $ (3,429.3 ) $ 23.6 $ (1.8 ) $ (15,449.9 ) Year Ended December 31, 2019 Foreign Unrealized Gain (Loss) on Unearned Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Balance, beginning of year $ (12,042.4 ) $ (3,429.3 ) $ 23.6 $ (1.8 ) $ (15,449.9 ) Exchange differences arising on translation of foreign operations (14,693.5 ) — — — (14,693.5 ) Unrealized gain (loss) on financial assets at FVTOCI Equity instruments — 334.5 — — 334.5 Debt instruments — 3,097.3 — — 3,097.3 Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — (162.1 ) — — (162.1 ) Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — (537.8 ) — — (537.8 ) Loss allowance adjustments from debt instruments — 6.9 — — 6.9 Gain (loss) arising on changes in the fair value of hedging instruments — — (109.6 ) — (109.6 ) Other comprehensive income transferred to profit or loss due to disposal of subsidiary 4.6 — — — 4.6 Transferred to initial carrying amount of hedged items — — 82.3 — 82.3 Share of other comprehensive income (loss) of associates (140.1 ) (11.8 ) (0.1 ) — (152.0 ) Share of unearned stock-based employee compensation of associates — — — 1.6 1.6 Income tax effect — 9.4 — — 9.4 Balance, end of year $ (26,871.4 ) $ (692.9 ) $ (3.8 ) $ (0.2 ) $ (27,568.3 ) Year Ended December 31, 2020 Foreign Unrealized Gain (Loss) on Unearned Total NT$ NT$ NT$ NT$ NT$ Balance, beginning of year $ (26,871.4 ) $ (692.9 ) $ (3.8 ) $ (0.2 ) $ (27,568.3 ) Exchange differences arising on translation of foreign operations (29,846.8 ) — — — (29,846.8 ) Unrealized gain (loss) on financial assets at FVTOCI Equity instruments — 423.2 — — 423.2 Debt instruments — 3,907.0 — — 3,907.0 Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — 108.7 — — 108.7 Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — (1,439.4 ) — — (1,439.4 ) Loss allowance adjustments from debt instruments — (0.9 ) — — (0.9 ) Gain (loss) arising on changes in the fair value of hedging instruments — — 24.1 — 24.1 Transferred to initial carrying amount of hedged items — — (20.3 ) — (20.3 ) Share of other comprehensive income (loss) of associates (283.4 ) 15.5 — — (267.9 ) Share of unearned stock-based employee compensation of associates — — — 0.2 0.2 Income tax effect — 0.6 — — 0.6 Balance, end of year $ (57,001.6 ) $ 2,321.8 $ — $ — $ (54,679.8 ) The aforementioned other equity includes the changes in other equities of TSMC and TSMC’s share of its subsidiaries and associates.

Net Revenue

Net Revenue	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Net Revenue	24. NET REVENUE a. Disaggregation of revenue from contracts with customers Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Product (In Millions) (In Millions) (In Millions) Wafer $ 911,296.4 $ 927,317.3 $ 1,178,456.3 Others 120,177.2 142,668.1 160,798.5 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Geography (In Millions) (In Millions) (In Millions) Taiwan $ 78,260.8 $ 84,255.2 $ 129,082.9 United States 632,821.5 634,713.0 817,911.0 China 175,794.2 208,101.4 233,783.3 Europe, the Middle East and Africa 71,068.5 67,568.2 70,213.4 Japan 58,125.9 57,468.6 63,299.2 Others 15,402.7 17,879.0 24,965.0 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 The Company categorized the net revenue mainly based on the countries where the customers are headquartered. Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Platform (In Millions) (In Millions) (In Millions) Smartphone $ 466,452.3 $ 523,612.9 $ 645,303.6 High Performance Computing 341,910.2 315,822.3 439,810.0 Internet of Things 65,091.3 86,342.7 110,355.2 Automotive 51,709.8 47,914.5 44,367.5 Digital Consumer Electronics 58,470.2 53,733.4 54,555.7 Others 47,839.8 42,559.6 44,862.8 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Resolution (In Millions) (In Millions) (In Millions) 5-nanometer $ — $ — $ 90,934.5 7-nanometer 81,680.7 249,548.1 394,837.0 10-nanometer 96,989.5 23,266.4 3,403.1 16-nanometer 187,370.6 186,700.9 197,959.0 20-nanometer 23,618.4 9,535.8 8,450.9 28-nanometer 178,440.4 149,578.7 149,367.7 40/45-nanometer 101,801.0 93,366.3 103,176.5 65-nanometer 76,122.3 69,250.0 61,226.7 90-nanometer 36,652.1 25,624.2 29,380.4 0.11/0.13 micron 20,677.7 22,947.3 33,197.1 0.15/0.18 micron 81,182.6 77,564.5 86,008.5 0.25 micron and above 26,761.1 19,935.1 20,514.9 Wafer revenue $ 911,296.4 $ 927,317.3 $ 1,178,456.3 Starting the first qu a b. Contract balances January 1, 2019 December 31, 2019 December 31, 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Contract liabilities (classified under accrued expenses and other current liabilities) $ 4,684.0 $ 6,784.3 $ 13,775.1 The changes in the contract liability balances primarily result from the timing difference between the satisfaction of performance obligation and the customer’s payment. The Company recognized revenue from the beginning balance of contract liability, which amounted to NT$31,770.0 million, NT$3,876.6 million and NT$4,737.9 million for the years ended December 31, 2018, 2019 and 2020, respectively. c. Refund liabilities Estimated sales returns and other allowances is made and adjusted based on historical experience and the consideration of varying contractual terms, which amounted to NT$55,406.0 million, NT$36,211.4 million and NT$40,453.1 million for the years ended December 31, 2018, 2019 and 2020, respectively. As of December 31, 2019 and 2020, the aforementioned refund liabilities amounted to NT$19,620.2 million and NT$33,194.8 million (classified under accrued expenses and other current liabilities), respectively.

Interest Income

Interest Income	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Interest Income	25. INTEREST INCOME Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Interest income Bank deposit s $ 10,310.7 $ 11,454.0 $ 5,139.1 Financial assets at FVTPL 382.7 339.5 2.5 Financial assets at FVTOCI 3,078.6 3,476.2 3,121.9 Financial assets at amortized cost 922.4 919.7 754.9 $ 14,694.4 $ 16,189.4 $ 9,018.4

Finance Costs

Finance Costs	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Finance Costs	26. FINANCE COSTS Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Interest expense Corporate bo n $ 1,633.8 $ 1,139.9 $ 1,337.3 Bank loans 1,417.3 1,869.4 500.9 Lease liabilities — 240.9 227.8 Others 0.1 0.7 15.5 $ 3,051.2 $ 3,250.9 $ 2,081.5

Other Gains and Losses, Net

Other Gains and Losses, Net	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Other Gains and Losses, Net	27. OTHER GAINS AND LOSSES, NET Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Gain (loss) on disposal of financial assets, net Investments in debt instruments at FVTOCI $ (989.1 ) $ 537.8 $ 1,439.4 Loss on disposal of subsidiaries — (4.6 ) — Gain (loss) on financial instruments at FVTPL, net Mandatorily measured at FVT P (2,293.9 ) (2,360.7 ) 8,244.5 Gain (loss) arising from fair value hedges, net (2.3 ) 13.1 — The reversal (accrual) of expected credit loss of financial assets Investments in debt instruments at FVTOCI 2.0 (6.9 ) 0.9 Financial assets at amortized cost 0.4 5.2 (4.6 ) Other gains (losses), net (127.9 ) 665.1 426.2 $ (3,410.8 ) $ (1,151.0 ) $ 10,106.4

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Income Tax	28. INCOME TAX a. Income tax expense recognized in profit or loss Income tax expense consisted of the following: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Current income tax expense Current tax expense recognized in the current year $ 60,584.3 $ 47,135.5 $ 87,452.7 Income tax adjustments on prior years (21,753.0 ) (10,193.8 ) (7,589.4 ) Other income tax adjustments 152.9 (41.5 ) 150.2 38,984.2 36,900.2 80,013.5 Deferred income tax benefit Effect of tax rate changes (1,474.8 ) — — The origination and reversal of temporary differences (3,072.5 ) (1,065.1 ) (6,275.2 ) (4,547.3 ) (1,065.1 ) (6,275.2 ) Income tax expense recognized in profit or loss $ 34,436.9 $ 35,835.1 $ 73,738.3 A reconciliation of inc o Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Income before tax $ 397,543.1 $ 389,862.1 $ 584,746.3 Income tax expense at the statutory rate $ 80,872.5 $ 79,056.5 $ 118,831.3 Tax effect of adjusting items: Nondeductible (deductible) items in determining taxable income 2,533.4 (4,183.5 ) 1,015.9 Tax-exempt (54,543.5 ) (39,808.1 ) (65,988.1 ) Additional income tax under the Alternative Minimum Tax Act 21,455.9 10,367.9 18,872.8 Additional income tax on unappropriated earnings 16,294.5 7,628.1 14,747.3 Effect of tax rate changes on deferred income tax (1,474.8 ) — — The origination and reversal of temporary differences (3,072.6 ) (1,065.1 ) (6,275.2 ) Income tax credits (6,028.4 ) (5,925.4 ) (26.5 ) 56,037.0 46,070.4 81,177.5 Income tax adjustments on prior years (21,753.0 ) (10,193.8 ) (7,589.4 ) Other income tax adjustments 152.9 (41.5 ) 150.2 Income tax expense recognized in profit or loss $ 34,436.9 $ 35,835.1 $ 73,738.3 In 2018, the Income Tax Law in the R.O.C. was amended and, starting from 2018, the corporate income tax rate was adjusted from 17% to 20%. In addition, the tax rate for 2018 unappropriated earnings was reduced from 10% to 5%. Under the amendment to the R.O.C Statute of Industrial Innovation in 2019, the amounts of unappropriated earnings in 2018 and thereafter used for building or purchasing specific assets or technologies can qualify for deduction when computing the income tax on unappropriated earnings. The income tax adjustments on prior years were primarily due to the difference between the actual and estimated income tax on unappropriated earnings. For other jurisdictions, taxes are calculated using the applicable tax rate for each individual jurisdiction. b. Income tax expense recognized in other comprehensive income Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Deferred income tax benefit (expense) Related to remeasurement of defined benefit obligation $ 103.3 $ (30.4 ) $ 422.1 Related to unrealized gain/loss on investments in equity instruments at FVTOCI 91.8 9.4 0.6 Related to gain/loss on cash flow hedges 0.6 — — $ 195.7 $ (21.0 ) $ 422.7 c. Deferred income tax balance The analysis of deferred income tax assets and liabilities was as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 13,547.2 $ 19,354.4 Refund liability 2,150.4 3,755.1 Net defined benefit liability 1,016.3 1,342.1 Unrealized loss on inventories 469.4 858.5 Deferred compensation cost 323.1 330.3 Investments in equity instruments at FVTOCI 65.7 66.3 Others 356.3 251.5 $ 17,928.4 $ 25,958.2 Deferred income tax liabilities Temporary differences Unrealized exchange gains (333.6 ) (866.5 ) Others (10.8 ) (863.4 ) $ (344.4 ) $ (1,729.9 ) Year Ended December 31, 2018 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 8,401.3 $ 3,430.4 $ — $ 7.5 $ 11,839.2 Refund liability 1,637.7 955.0 — 1.3 2,594.0 Net defined benefit liability 975.3 6.3 103.3 — 1,084.9 Unrealized loss on inventories 629.5 120.5 — 1.0 751.0 Deferred compensation cost 266.5 (4.7 ) — 9.9 271.7 Investments in equity instruments at FVTOCI — — 56.2 — 56.2 Others 195.2 7.1 — 7.1 209.4 $ 12,105.5 $ 4,514.6 $ 159.5 $ 26.8 $ 16,806.4 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (169.5 ) $ 107.8 $ — $ — $ (61.7 ) Investments in equity instruments at FVTOCI (95.4 ) — 95.4 — — Others (37.3 ) (75.1 ) (59.2 ) — (171.6 ) $ (302.2 ) $ 32.7 $ 36.2 $ — $ (233.3 ) Year Ended December 31, 2019 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 11,839.2 $ 1,727.8 $ — $ (19.8 ) $ 13,547.2 Refund liability 2,594.0 (443.2 ) — (0.4 ) 2,150.4 Net defined benefit liability 1,084.9 (38.2 ) (30.4 ) — 1,016.3 Unrealized loss on inventories 751.0 (280.8 ) — (0.8 ) 469.4 Deferred compensation cost 271.7 59.4 — (8.0 ) 323.1 Investments in equity instruments at FVTOCI 56.2 0.1 9.4 — 65.7 Others 209.4 151.1 — (4.2 ) 356.3 $ 16,806.4 $ 1,176.2 $ (21.0 ) $ (33.2 ) $ 17,928.4 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (61.7 ) $ (271.9 ) $ — $ — $ (333.6 ) Others (171.6 ) 160.8 — — (10.8 ) $ (233.3 ) $ (111.1 ) $ — $ — $ (344.4 ) Year Ended December 31, 2020 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 13,547.2 $ 5,824.0 $ — $ (16.8 ) $ 19,354.4 Refund liability 2,150.4 1,606.1 — (1.4 ) 3,755.1 Net defined benefit liability 1,016.3 (96.3 ) 422.1 — 1,342.1 Unrealized loss on inventories 469.4 391.1 — (2.0 ) 858.5 Deferred compensation cost 323.1 27.4 — (20.2 ) 330.3 Investments in equity instruments at FVTOCI 65.7 — 0.6 — 66.3 Others 356.3 (91.6 ) — (13.2 ) 251.5 $ 17,928.4 $ 7,660.7 $ 422.7 $ (53.6 ) $ 25,958.2 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (333.6 ) $ (532.9 ) $ — $ — $ (866.5 ) Others (10.8 ) (852.6 ) — — (863.4 ) $ (344.4 ) $ (1,385.5 ) $ — $ — $ (1,729.9 ) d. The deductible temporary differences for which no deferred income tax assets have been recognized As of December 31, 2019 and 2020, the aggregate deductible temporary differences for which no deferred income tax assets have been recognized amounted to NT$33,445.5 million and NT$55,521.0 million, respectively. e. Unused tax-exemption As of December 31, 2020, the profits generated from the following projects of TSMC are exempt from income tax for a five-year period: Tax-exemption Period Construction and expansion of 2009 by TSMC 2018 to 2022 f. The information of unrecognized deferred income tax liabilities associated with investments As of December 31, 2019 and 2020, the aggregate taxable temporary differences associated with investments in subsidiaries not recognized as deferred income tax liabilities amounted to NT$131,085.7 million and NT$152,827.4 million, respectively. g. Income tax examination The tax authorities have examined income tax returns of TSMC through 2018. All investment tax credit adjustments assessed by the tax authorities have been recognized accordingly.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Earnings Per Share	29. EARNINGS PER SHARE Years Ended December 31 2018 2019 2020 (NT$) (NT$) (NT$) Basic EPS $ 14.00 $ 13.65 $ 19.70 Diluted EPS $ 14.00 $ 13.65 $ 19.70 EPS is computed as follows: Amounts NT$ (In Millions) Number of EPS (NT$) Year Ended December 31, 2018 Basic/Diluted EPS Net income available to common shareholders of the parent $ 363,052.7 25,930.3 $ 14.00 Year Ended December 31, 2019 Basic/Diluted EPS Net income available to common shareholders of the parent $ 353,948.0 25,930.3 $ 13.65 Amounts NT$ (In Millions) Number of EPS (NT$) Year Ended December 31, 2020 Basic/Diluted EPS Net income available to common shareholders of the parent $ 510,744.0 25,930.3 $ 19.70

Additional Information of Expen

Additional Information of Expenses by Nature	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Additional Information of Expenses by Nature	30. ADDITIONAL INFORMATION OF EXPENSES BY NATURE Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) a.   Depreciation of property, plant and equipment and right-of-use Recognized in cost of revenue $ 264,804.7 $ 256,530.9 $ 299,311.4 Recognized in operating expenses 23,292.3 24,856.7 25,191.3 Recognized in other operating income and expenses 27.9 24.2 35.7 $ 288,124.9 $ 281,411.8 $ 324,538.4 b.  Amortization of intangible assets Recognized in cost of revenue $ 2,073.5 $ 3,069.9 $ 4,837.7 Recognized in operating expenses 2,347.9 2,402.5 2,348.5 $ 4,421.4 $ 5,472.4 $ 7,186.2 c.   Employee benefits expenses Post-employment benefits Defined contribution plans $ 2,568.9 $ 2,609.7 $ 2,809.5 Defined benefit plans 281.8 259.6 204.9 2,850.7 2,869.3 3,014.4 Other employee benefits 105,364.2 107,115.3 137,803.0 $ 108,214.9 $ 109,984.6 $ 140,817.4 Employee benefits expense summarized by function Recognized in cost of revenue $ 63,597.7 $ 64,702.0 $ 83,099.0 Recognized in operating expenses 44,617.2 45,282.6 57,718.4 $ 108,214.9 $ 109,984.6 $ 140,817.4 According to TSMC’s Articles of Incorporation, TSMC shall allocate compensation to directors and profit sharing bonus to employees of TSMC not more than 0.3% and not less than 1% of annual profits during the period, respectively. TSMC accrued profit sharing bonus to employees based on a percentage of net income before income tax, profit sharing bonus to employees and compensation to directors during the period; compensation to directors was expensed based on estimated amount payable. If there is a change in the proposed amounts after the annual consolidated financial statements are authorized for issue, the differences are recorded as a change in accounting estimate. Accrued profit sharing bonus to employees is illustrated below: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Profit sharing bonus to employees $ 23,570.0 $ 23,165.7 $ 34,753.2 TSMC’s profit sharing bonus to employees and compensation to directors for 2018, 2019 and 2020 had been approved by the Board of Directors of TSMC, as illustrated below: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Resolution Date of TSMC’s Board of Directors in its meeting February 19, 2019 February 11, 2020 February 9, 2021 Profit sharing bonus to employees $ 23,570.0 $ 23,165.7 $ 34,753.2 Compensation to directors $ 349.3 $ 360.4 $ 509.8 There is no significant difference between the aforementioned approved amounts and the amounts charged against earnings of 2018, 2019 and 2020, respectively

Cash Flow Information

Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Cash Flow Information	31. CASH FLOW INFORMATION a.   Non-cash Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Additions of financial assets at FVTOCI $ 100,759.6 $ 257,824.5 $ 268,653.5 Conversion of convertible bonds into equity securities (23.8 ) — (120.5 ) Changes in accrued expenses and other current liabilities (4,323.0 ) (266.3 ) (5,895.5 ) Payments for acquisition of financial assets at FVTOCI $ 96,412.8 $ 257,558.2 $ 262,637.5 Disposal of financial assets at FVTOCI $ 90,545.1 $ 229,525.1 $ 269,011.8 Changes in other financial assets (3,905.8 ) 919.4 (2,079.9 ) Proceeds from disposal of financial assets at FVTOCI $ 86,639.3 $ 230,444.5 $ 266,931.9 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Additions of property, plant and equipment $ 300,024.4 $ 564,283.0 $ 525,720.7 Changes in other financial assets 1,555.4 472.5 584.7 Exchange of assets — (3,287.1 ) (1.1 ) Changes in payables to contractors and equipment suppliers 13,979.9 (100,963.9 ) (19,085.9 ) Transferred to initial carrying amount of hedged items 22.2 (82.3 ) 20.3 Payments for acquisition of property, plant and equipment $ 315,581.9 $ 460,422.2 $ 507,238.7 Additions of intangible assets $ 7,105.0 $ 9,237.7 $ 12,559.5 Changes in other financial assets 22.8 22.2 10.5 Changes in account payable (27.5 ) 70.0 191.4 Changes in accrued expenses and other current liabilities — — (3,219.0 ) Payments for acquisition of intangible assets $ 7,100.3 $ 9,329.9 $ 9,542.4 (Concluded) b. Reconciliation of liabilities arising from financing activities Non-cash changes Balance as of January 1, 2018 Financing Cash Flow Foreign Exchange Movement Other Changes (Note) Balance as of December 31, 2019 NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 63,766.8 $ 23,923.0 $ 1,064.9 $ — $ 88,754.7 Bonds payable 150,201.1 (58,024.9 ) (382.9 ) 6.7 91,800.0 Guarantee deposits 16,080.6 (279.2 ) 423.5 (6,035.9 ) 10,189.0 Total $ 230,048.5 $ (34,381.1 ) $ 1,105.5 $ (6,029.2 ) $ 190,743.7 Non-cash changes Balance as of Financing Cash Flow Foreign Exchange Movement Leases Modifications Other Changes (Note) Balance as of December 31, 2019 NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 88,754.7 $ 31,804.3 $ (2,036.7 ) $ — $ — $ 118,522.3 Bonds payable 91,800.0 (34,900.0 ) — — — 56,900.0 Lease liabilities 19,903.6 (3,174.0 ) (73.3 ) 419.7 240.9 17,316.9 Guarantee deposits 10,189.0 (639.1 ) 4.5 — (7,824.5 ) 1,729.9 Total $ 210,647.3 $ (6,908.8 ) $ (2,105.5 ) $ 419.7 $ (7,583.6 ) $ 194,469.1 Non-cash changes Balance as of Financing Cash Flow Foreign Exchange Movement Leases Modifications Other Changes (Note) Balance as of December 31, 2020 NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 118,522.3 $ (31,571.6 ) $ 1,608.3 $ — $ — $ 88,559.0 Bonds payable 56,900.0 204,535.0 (4,758.6 ) — 28.7 256,705.1 Long-term bank loans — 2,000.0 — — (32.4 ) 1,967.6 Lease liabilities 17,316.9 (2,819.7 ) (78.5 ) 7,742.2 227.7 22,388.6 Guarantee deposits 1,729.9 129.5 1.8 — (1,511.2 ) 350.0 Total $ 194,469.1 $ 172,273.2 $ (3,227.0 ) $ 7,742.2 $ (1,287.2 ) $ 369,970.3 Note: Other changes include amortization of bonds payable, amortization of long-term bank loan interest subsidy, financial cost of lease liabilities and guarantee deposits refunded to customers by offsetting related accounts receivable.

Capital Management

Capital Management	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Capital Management	32 CAPITAL MANAGEMENT The Company requires significant amounts of capital to build and expand its production facilities and acquire additional equipment. In consideration of the industry dynamics, the Company manages its capital in a manner to ensure that it has sufficient and necessary financial resources to fund its working capital needs, capital asset purchases, research and development activities, dividend payments, debt service requirements and other business requirements associated with its existing operations over the next 12 months.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Financial Instruments	33. FINANCIAL INSTRUMENTS a. Categories of financial instruments December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets FVTPL (Note 1) $ 326.8 $ 2,259.4 FVTOCI (Note 2) 134,776.8 129,918.7 Hedging financial assets 25.9 0.1 Amortized cost (Note 3) 612,740.6 826,293.6 $ 747,870.1 $ 958,471.8 Financial liabilities FVTPL (Note 4) $ 982.3 $ 94.1 Hedging financial liabilities 1.8 1.2 Amortized cost (Note 5) 533,581.7 748,129.3 $ 534,565.8 $ 748,224.6 Note 1: Financial assets mand a Note 2: Including notes and accounts receivable (net), equity and debt investments. Note 3: Including cash and cash equivalents, financial assets at amortized cost, notes and accounts receivable (including related parties), other receivables and refundable deposits. Note 4: Held for trading. Note 5: Including short-term loans, accounts payable (including related parties), payables to contractors and equipment suppliers, cash dividends payable, accrued expenses and other current liabilities, bonds payable, long-term bank loans and guarantee deposits. b. Financial risk management objectives The Company manages its exposure to f o The plans for material treasury activities are reviewed by Audit Committees and/or Board of Directors in accordance with procedures required by relevant regulations or internal controls. During the implementation of such plans, the Company must comply with certain treasury procedures that provide guiding principles for overall financial risk management and segregation of duties. c. Market risk The Company is exposed to the financial market risks, primarily changes in foreign currency exchange rates, interest rates and equity investment prices. A portion of these risks is hedged. Foreign currency risk The majority of the Company’s revenue is denominated in U.S. dollar and over one-half non-NT Based on a sensitivity analysis performed on the Company’s total monetary assets and liabilities for the years ended December 31, 2018, 2019 and 2020, a hypothetical adverse foreign currency exchange rate change of 10% would have decreased its net income by NT$506.4 million, NT$2,137.3 million and NT$897.7 million, respectively, and decreased its other comprehensive income by NT$315.6 million, NT$107.7 million for the years ended December 2018 and 2019, after taking into account hedges and offsetting positions. Interest rate risk The Company is exposed to interest rate risks primarily related to its investment portfolio and outstanding debt. Changes in interest rates affect the interest earned on the Company’s cash and cash equivalents and fixed income securities, the fair value of those securities, as well as the interest paid on its debt. The Company’s cash and cash equivalents as well as fixed income investments in both fixed- and floating-rate securities carry a degree of interest rate risk. The majority of the Company’s fixed income investments are fixed-rate securities, which are classified as financial assets at FVTOCI, and may have their fair value adversely affected due to a rise in interest rates. At the same time, if interest rates fall, cash and cash equivalents as well as floating-rate securities may generate less interest income than expected. The Company has entered and may in the future enter into interest rate futures to partially hedge the interest rate risk on its fixed income investments. However, these hedges can offset only a small portion of the financial impact from movements in interest rates. Based on a sensitivity analysis performed on the Company’s fixed income investments at the end of the reporting period, interest rates increase of 100 basis points (1.00%) across all maturities would have decreased the fair value by NT$2,697.8million, NT$3,517.4 million and NT$3,143.6 million for the years ended December 31, 2018, 2019 and 2020, respectively. The decreases were composed of NT$2,450.0 million decrease, NT$3,516.6 million decrease and NT$3,143.6 million decrease in other comprehensive income for the years ended December 31, 2018, 2019, and 2020, respectively, and NT$247.8 million decrease and NT$0.8 million decrease in net income for the years ended December 31, 2018 and 2019, respectively. d. Credit risk management Credit risk refers to the risk that a counterparty will default on its contractual obligations resulting in financial losses to the Company. The Company is exposed to credit risks from operating activities, primarily accounts receivable, and from investing activities, primarily deposits, fixed-income investments and other financial instruments with banks. Credit risk is managed separately for business related and financial related exposures. As of the end of the reporting period, the Company’s maximum credit risk exposure is equal to the carrying amount of financial assets. Business related credit risk The Company’s accounts receivable is from its customers worldwide. The majority of the Company’s outstanding accounts receivable are not covered by collaterals or guarantees. While the Company has procedures to monitor and manage credit risk exposure on accounts receivable, there is no assurance such procedures will effectively eliminate losses resulting from its credit risk. This risk is heightened during periods when economic conditions worsen. As of December 31, 2019 and 2020, the Company’s ten largest customers accounted for 79% of accounts receivable in both years. The Company considers the concentration of credit risk for the remaining accounts receivable not material. Financial credit risk The Company mitigates its financial credit risk by selecting counterparties with investment grade credit ratings and by limiting the exposure to any individual counterparty. The Company regularly monitors and reviews the limit applied to counterparties and adjusts the limit according to market conditions and the credit standing of the counterparties. The objective of the Company’s investment policy is to achieve a return that will allow the Company to preserve principal and support liquidity requirements. The policy generally requires securities to be investment grade and limits the amount of credit exposure to any one issuer. The Company assesses whether there has been a significant increase in credit risk in the invested securities since initial recognition by reviewing changes in external credit ratings, financial market conditions and material information of the issuers. The Company assesses the 12-month Category Description Basis for Recognizing Expected Credit Loss Expected Performing Credit rating is investment grade on valuation date 12 months expected credit loss 0—0.1% Doubtful Credit rating is non-investment Lifetime expected credit loss-not — In default Credit rating is CC or below on valuation date Lifetime expected credit loss-credit impaired — Write-off There is evidence indicating that the debtor is in severe financial difficulty and the Company has no realistic prospect of recovery Amount is written off — For the years ended December 31, 2018, 2019 and 2020, the expected credit loss decreases NT$1.1 million, increases NT$0.6 million and increases NT$1.1 million, respectively. The changes are mainly due to investment portfolio adjustment and changes in credit rating of investment securities. e. Liquidity risk management The objective of liquidity risk management is to ensure the Company has sufficient liquidity to fund its business operations over the next 12 months. The Company manages its liquidity risk by maintaining adequate cash and cash equivalents, fixed income investments at FVTPL, financial assets at FVTOCI-current, financial assets at amortized cost-current and sufficient cost-efficient funding. The table below summarizes the maturity profile of the Company’s financial liabilities based on contractual undiscounted payments, including principal and interest. Less Than 1 Year 1-3 Years 3-5 Years More Than 5 Years Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) December 31, 2019 Non-derivative Short-term loans $ 118,562.6 $ — $ — $ — $ 118,562.6 Accounts payable (including related parties) 40,206.0 — — — 40,206.0 Payables to contractors and equipment suppliers 140,810.7 — — — 140,810.7 Accrued expenses and other current liabilities 45,760.9 — — — 45,760.9 Bonds payable 32,338.9 7,777.7 18,203.6 — 58,320.2 Lease liabilities (including those classified under accrued expenses and other current liabilities) 2,475.1 2,782.9 2,484.5 10,947.7 18,690.2 Guarantee deposits (including those classified under accrued expenses and other current liabilities) 1,553.0 121.0 55.5 0.4 1,729.9 381,707.2 10,681.6 20,743.6 10,948.1 424,080.5 Derivative financial instruments Forward exchange contracts Outflows 141,450.8 — — — 141,450.8 Inflows (141,128.9 ) — — — (141,128.9 ) 321.9 — — — 321.9 $ 382,029.1 $ 10,681.6 $ 20,743.6 $ 10,948.1 $ 424,402.4 December 31, 2020 Non-derivative Short-term loans $ 88,557.5 $ — $ — $ — $ 88,557.5 Accounts payable (including related parties) 41,095.0 — — — 41,095.0 Payables to contractors and equipment suppliers 157,805.0 — — — 157,805.0 Accrued expenses and other current liabilities 71,995.7 — — — 71,995.7 Bonds payable 5,328.0 27,631.6 59,986.8 207,152.1 300,098.5 Long-term bank loans 8.0 847.4 1,170.9 — 2,026.3 Lease liabilities (including those classified under accrued expenses and other current liabilities) 2,024.2 3,566.7 3,198.8 15,067.9 23,857.6 Guarantee deposits (including those classified under accrued expenses and other current liabilities) 84.4 113.5 151.8 0.3 350.0 366,897.8 32,159.2 64,508.3 222,220.3 685,785.6 Derivative financial instruments Forward exchange contracts Outflows 177,764.2 — — — 177,764.2 Inflows (181,458.0 ) — — — (181,458.0 ) (3,693.8 ) — — — (3,693.8 ) $ 363,204.0 $ 32,159.2 $ 64,508.3 $ 222,220.3 $ 682,091.8 Information about the maturity analysis for lease liabilities more than 5 years: 5-10 10-15 15-20 More Than 20 Years Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) December 31, 2019 Lease liabilities $ 5,581.1 $ 3,691.3 $ 1,600.9 $ 74.4 $ 10,947.7 December 31, 2020 Lease liabilities $ 7,402.0 $ 5,253.9 $ 2,255.2 $ 156.8 $ 15,067.9 f. Fair value of financial instruments 1) Fair value measurements recognized in the consolidated statements of financial position Fair value measurements are grouped into Levels 1 to 3 based on the degree to which the fair value is observable: • Level 1 fair value measurements are those derived from quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2 fair value measurements are those derived from inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly (i.e. as prices) or indirectly (i.e. derived from prices); and • Level 3 fair value measurements are those derived from valuation techniques that include inputs for the asset or liability that are not based on observable market data (unobservable inputs). The timing of transfers between levels within the fair value hierarchy is at the end of reporting period. 2) Fair value of financial instruments that are measured at fair value on a recurring basis Fair value hierarchy The following table presents the Company’s financial assets and liabilities measured at fair value on a recurring basis: December 31, 2019 Level 1 Level 2 Level 3 Total NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) Financial assets at FVTPL Mandatorily measured at FVTPL Forward exchange contracts $ — $ 162.1 $ — $ 162.1 Convertible bonds — — 123.8 123.8 Agency mortgage-backed securities — 40.9 — 40.9 $ — $ 203.0 $ 123.8 $ 326.8 Financial assets at FVTOCI Investments in debt instruments Agency bonds/Agency mortgage-backed securities $ — $ 51,966.5 $ — $ 51,966.5 Corporate bonds — 51,790.0 — 51,790.0 Government bonds 12,678.1 146.1 — 12,824.2 Asset-backed securities — 10,815.9 — 10,815.9 Investments in equity instruments Non-publicly — 39.2 4,085.1 4,124.3 Notes and accounts receivable, net — 3,255.9 — 3,255.9 $ 12,678.1 $ 118,013.6 $ 4,085.1 $ 134,776.8 Hedging financial assets Fair value hedges Interest rate futures contracts $ 22.4 $ — $ — $ 22.4 Cash flow hedges Forward exchange contracts — 3.5 — 3.5 $ 22.4 $ 3.5 $ — $ 25.9 Financial liabilities at FVTPL Held for trading Forward exchange contracts $ — $ 982.3 $ — $ 982.3 Hedging financial liabilities Cash flow hedges Forward exchange contracts $ — $ 1.8 $ — $ 1.8 December 31, 2020 Level 1 Level 2 Level 3 Total NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) Financial assets at FVTPL Mandatorily measured at FVTPL Forward exchange contracts $ — $ 2,259.4 $ — $ 2,259.4 Financial assets at FVTOCI Investments in debt instruments Corporate bonds $ — $ 56,593.6 $ — $ 56,593.6 Agency bonds/Agency mortgage-backed securities — 43,977.1 — 43,977.1 Government bonds 13,279.2 180.3 — 13,459.5 Asset-backed securities — 8,368.3 — 8,368.3 Investments in equity instruments Non-publicly — — 4,514.9 4,514.9 Publicly traded stocks 50.0 — — 50.0 Notes and accounts receivable, net — 2,955.3 — 2,955.3 $ 13,329.2 $ 112,074.6 $ 4,514.9 $ 129,918.7 Hedging financial assets Fair value hedges Interest rate futures contracts $ 0.1 $ — $ — $ 0.1 Financial liabilities at FVTPL Held for trading Forward exchange contracts $ — $ 94.1 $ — $ 94.1 Hedging financial liabilities Fair value hedges Interest rate futures contracts $ 1.2 $ — $ — $ 1.2 The transfer from Level 2 to Level 1 is because quoted prices (unadjusted) in active markets became available for such equity investment. Reconciliation of Level 3 fair value measurements of financial assets The financial assets measured at Level 3 fair value we r Reconciliation of Level 3 fair value measurements of financial assets The financial assets measured at Level 3 fair value were financial assets at FVTPL and equity investments classified as financial assets at FVTOCI. Reconciliations for the years ended December 31, 2018, 2019 and 2020 were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 5,841.4 $ 3,910.7 $ 4,208.9 Additions 212.5 372.3 175.2 Recognized in profit or loss — — (3.8 ) Recognized in other comprehensive income (2,141.4 ) 129.5 409.0 Disposals and proceeds from return of capital of investments (175.8 ) (76.5 ) (51.1 ) Transfers out of level 3 (Note) — (43.6 ) — Effect of exchange rate changes 174.0 (83.5 ) (223.3 ) Balance, end of year $ 3,910.7 $ 4,208.9 $ 4,514.9 Note: The transfer from Level 3 to Level 2 is because observable market data became available for such equity investment. Valuation techniques and assumptions used in Level 2 fair value measurement The fair values of financial assets and financial liabilities are determined as follows: • The fair values of corporate bonds, agency bonds, agency mortgage-backed securities, asset-backed securities, government bonds and non-publicly • Forward exchange contracts are measured using forward exchange rates and discount rates derived from quoted market prices. • The fair value of accounts receivable classified as at FVTOCI is determined by the present value of future cash flows based on the discount rate that reflects the credit risk of counterparties. Valuation techniques and assumptions used in Level 3 fair value measurement The fair values of non-publicly The asset approach takes into account the net asset value measured at the fair value by independent parties. On December 31, 2019 and 2020, the Company uses unobservable inputs derived from discount for lack of marketability by 10%. When other inputs remain equal, the fair value will decrease by NT$34.8 million and NT39.0 million if discounts for lack of marketability increase by 1%. For the remaining few investments, the market approach is used to arrive at their fair values, for which the recent financing activities of investees, the market transaction prices of the similar companies and market conditions are considered. In addition, the fair values of convertible bonds are determined by the present value of future cash flow based on a discount rate reflecting issuer’s credit spread and market conditions, combined with the fair value of conversion option estimated by the option pricing model considering recent financing activities of the investee and market transaction prices of the similar companies. 3) Fair value of financial instruments that are not measured at fair value Except as detailed in the following table, the Company considers that the carrying amounts of financial instruments in the consolidated financial statements that are not measured at fair value approximate their fair values. Fair value hierarchy The table below sets out the fair value hierarchy for the Company’s financial assets and liabilities which are not required to measure at fair value: December 31, 2019 Carrying Level 2 Amount Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets Financial assets at amortized costs Corporate bonds $ 7,648.8 $ 7,718.7 Financial liabilities Financial liabilities at amortized costs Bonds payable $ 56,900.0 $ 57,739.1 December 31, 2020 Carrying Level 2 Amount Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets Financial assets at amortized costs Corporate bonds $ 10,970.2 $ 11,053.6 Financial liabilities Financial liabilities at amortized costs Bonds payable $ 256,705.1 $ 257,551.2 Valuation techniques and assumptions used in Level 2 fair value measurement The fair values of corporate bonds and the Company’s bonds payable are determined by quoted market prices provided by third party pricing services.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Related Party Transactions	34. RELATED PARTY TRANSACTIONS Intercompany balances and transactions between TSMC and its subsidiaries, which are related parties of TSMC, have been eliminated upon consolidation; therefore, those items are not disclosed in this note. The following is a summary of significant transactions between the Company and other related parties: a. Related party name and categories Related Party Name Related Party Categories GUC Associates VIS Associates SSMC Associates Xintec Associates TSMC Education and Culture Foundation Other related parties TSMC Charity Foundation Other related parties b. Net revenue Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Item Related Party Categories Net revenue from sale of goods Associates $ 8,980.1 $ 6,253.9 $ 8,129.8 Other related parties 0.3 — — $ 8,980.4 $ 6,253.9 $ 8,129.8 Net revenue from royalties Associates $ 362.3 $ 183.6 $ 195.1 c. Purchases Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Related Party Categories Associates $ 8,809.5 $ 6,301.4 $ 7,606.4 d. Receivables from related parties December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Item Related Party Name/Categories Receivables from related parties GUC $ 741.9 $ 370.6 Xintec 120.2 187.5 $ 862.1 $ 558.1 Other receivables from related parties SSMC $ 46.5 $ 45.3 VIS 3.9 4.3 Other associates 1.2 1.0 $ 51.6 $ 50.6 e. Payables to related parties December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Item Related Party Name/Categories Payables to related parties Xintec $ 736.9 $ 1,358.6 SSMC 487.9 400.8 VIS 154.0 311.4 Other associates 56.1 36.9 $ 1,434.9 $ 2,107.7 f. Others Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Item Related Party Categories Manufacturing expenses Associates $ 2,974.6 $ 2,823.0 $ 5,440.0 Research and development expenses Associates $ 83.1 $ 163.4 $ 256.5 General and administrative expenses Other related parties $ 120.8 $ 120.0 $ 120.0 The sales prices and payment terms to related parties were not significantly different from those of sales to third parties. For other related party transactions, price and terms were determined in accordance with mutual agreements. The Company leased factory and office from associates. The lease terms and prices were both determined in accordance with mutual agreements. The rental expenses were paid to associates monthly; the related expenses were both classified under manufacturing expenses. g. Compensation of key management personnel The compensation to directors and other key management personnel were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Short-term employee benefits $ 2,004.9 $ 1,922.2 $ 2,666.7 Post-employment benefits 3.4 2.7 2.3 $ 2,008.3 $ 1,924.9 $ 2,669.0 The compensation to directors and other key management personnel were determined by the Compensation Committee of TSMC in accordance with the individual performance and the market trends.

Pledged Assets

Pledged Assets	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Pledged Assets	35. PLEDGED ASSETS The Company provided certificate of deposits recorded in other financial assets as collateral mainly for building lease agreements. As of December 31, 2019 and 2020, the aforementioned other financial assets amounted to NT$114.5 million and NT$135.4 million, respectively.

Significant Contingent Liabilit

Significant Contingent Liabilities and Unrecognized Commitments	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Significant Contingent Liabilities and Unrecognized Commitments	36. SIGNIFICANT CONTINGENT LIABILITIES AND UNRECOGNIZED COMMITMENTS Significant contingent liabilities and unrecognized commitments of the Company as of the end of the reporting period, excluding those disclosed in other notes, were as follows: a. Under a technical cooperation agreement with Industrial Technology Research Institute, the R.O.C. Government or its designee approved by TSMC can use up to 35% of TSMC’s capacity provided TSMC’s outstanding commitments to its customers are not prejudiced. The term of this agreement is for five years beginning from January 1, 1987 and is automatically renewed for successive periods of five years unless otherwise terminated by either party with one year prior notice. As of December 31, 2020, the R.O.C. Government did not invoke such right. b. Under a Shareholders Agreement entered into with Philips and EDB Investments Pte Ltd. on March 30, 1999, the parties formed a joint venture company, SSMC, which is an integrated circuit foundry in Singapore. TSMC’s equity interest in SSMC was 32%. Nevertheless, in September 2006, Philips spun-off c. On September 28, 2017, TSMC was contacted by the European Commission (the “Commission”), which asked us for information and documents concerning alleged anti-competitive practices in relation to semiconductor sales. We cooperated continuously with the Commission to provide the requested information and documents. The Commission subsequently decided to close the investigation in May 2020. d. TSMC entered into long-term purchase agreements of materials and supplies with multiple suppliers. The relative minimum purchase quantity and price are specified in the agreements. e. TSMC entered into a long-term purchase agreement of equipment. The relative purchase quantity and price are specified in the agreement. f. TSMC entered into long-term energy purchase agreements with multiple suppliers. The relative purchase period, quantity and price are specified in the agreements. g. Amounts available under unused letters of credit as of December 31, 2019 and 2020 were NT$60.0 million and NT$56.2 million, respectively.

Significant Operation Losses

Significant Operation Losses	12 Months Ended
	Dec. 31, 2020
Disclosure of Significant Operation Losses [Abstract]
Significant Operation Losses	37. SIGNIFICANT OPERATION LOSSES The Company experienced a computer virus outbreak on August 3, 2018, which affected a number of computer systems and fab tools, and consequently impacted wafer production in Taiwan. All the impacted tools have been recovered by August 6, 2018. The Company recognized a loss of NT$2,596.0 million related to this incident for the three months ended September 30, 2018, which was included in cost of revenue. On January 19, 2019, the Company discovered a wafer contamination issue in a fab in Taiwan caused by a batch of unqualified photoresist materials. After investigation, the Company immediately stopped using the unqualified materials. An estimated loss of NT$3,400.0 million related to this event was recognized in cost of revenue for the three months ended March 31, 2019.

Operating Segments Information

Operating Segments Information	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Operating Segments Information	38. OPERATING SEGMENTS INFORMATION a. Operating segments, segment revenue and operating results TSMC’s chief operating decision makers periodically review operating results, focusing on operating income generated by foundry segment. Operating results are used for resource allocation and/or performance assessment. As a result, the Company has only one operating segment, the foundry segment. The foundry segment engages mainly in the manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing of masks. The basis for the measurement of income from operations is the same as that for the preparation of financial statements. Please refer to the consolidated statements of comprehensive income for the related segment revenue and operating results. b. Geographic and major customers’ information were as follows: 1) Geographic information December 31, December 31, 2019 2020 NT$ NT$ Noncurrent Assets (In Millions) (In Millions) Taiwan $ 1,344,352.6 $ 1,569,080.4 United States 8,850.1 9,455.5 China 38,586.6 34,456.4 Europe, the Middle East and Africa 186.2 174.2 Japan 27.1 327.2 Others 3.1 3.0 $ 1,392,005.7 $ 1,613,496.7 Noncurrent assets include property, plant and equipment, right-of-use 2) Major custom e Years Ended December 31 2018 2019 2020 Amount % Amount % Amount % NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Customer A $ 224,690.7 22 $ 247,213.3 23 $ 336,775.5 25 Customer B 83,885.6 8 152,876.9 14 167,390.8 12

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Statement of Compliance	Statement of Compliance The accompanying consolidated financial statements have been prepared in accordance with IFRSs.
Basis of Preparation	Basis of Preparation The accompanying consolidated financial statements have been prepared on the historical cost basis except for financial instruments that are measured at fair values, as explained in the accounting policies below. Historical cost is generally based on the fair value of the consideration given in exchange for the assets.
Basis of Consolidation	Basis of Consolidation The basis for the consolidated financial statements The consolidated financial statements incorporate the financial statements of TSMC and entities controlled by TSMC (its subsidiaries). Income and expenses of subsidiaries acquired or disposed of are included in the consolidated statements of profit or loss and other comprehensive income from the effective date of acquisition and up to the effective date of disposal, as appropriate. Total comprehensive income of subsidiaries is attributed to the shareholders of the parent and to the non-controlling interests even if this results in the non-controlling interests having a deficit balance. When necessary, adjustments are made to the financial statements of subsidiaries to bring their accounting policies into line with those used by the Company. All intra-group transactions, balances, income and expenses are eliminated in full on consolidation. Changes in the Company’s ownership interests in subsidiaries that do not result in the Company losing control over the subsidiaries are accounted for as equity transactions. The carrying amounts of the Company’s interests and the non-controlling interests are adjusted to reflect the changes in their relative interests in the subsidiaries. Any difference between the amount by which the non-controlling interests are adjusted and the fair value of the consideration paid or received is recognized directly in equity and attributed to shareholders of the parent. When the Company loses control of a subsidiary, a gain or loss is recognized in profit or loss and is calculated as the difference between: a. the aggregate of the fair value of consideration received and the fair value of any retained interest at the date when control is lost; and b. the previous carrying amount of the assets (including goodwill), and liabilities of the subsidiary and any non-controlling interest. The Company shall account for all amounts recognized in other comprehensive income in relation to the subsidiary on the same basis as would be required if the Company had directly disposed of the related assets and liabilities. The fair value of any investment retained in the former subsidiary at the date when control is lost is regarded as the cost on initial recognition of an investment in an associate. The subsidiaries in the consolidated financial statements The detail information of the subsidiaries at the end of reporting period was as follows: Percentage of Ownership Name of Investor Name of Investee Main Businesses and Products Establishment and Operating December 31, 2019 December 31, 2020 Note TSMC TSMC North America Selling and marketing of integrated circuits and other semiconductor devices San Jose, California, U.S.A. 100% 100% — TSMC Europe B.V. (TSMC Europe) Customer service and supporting activities Amsterdam, the Netherlands 100% 100% a) TSMC Japan Limited (TSMC Japan) Customer service and supporting activities Yokohama, Japan 100% 100% a) TSMC Design Technology Japan, Inc. (TSMC JDC) Engineering support activities Yokohama, Japan — 100% a), b) TSMC Korea Limited (TSMC Korea) Customer service and supporting activities Seoul, Korea 100% 100% a) TSMC TSMC Partners, Ltd. (TSMC Partners) Investing in companies involved in the design, manufacture, and other related business in the semiconductor industry and other investment activities Tortola, British Virgin Islands 100% 100% a) TSMC Global, Ltd. (TSMC Global) Investment activities Tortola, British Virgin Islands 100% 100% — TSMC China Company Limited (TSMC China) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Shanghai, China 100% 100% — TSMC Nanjing Company Limited (TSMC Nanjing) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Nanjing, China 100% 100% d) VisEra Technologies Company Ltd. (VisEra Tech) Engaged in manufacturing electronic spare parts and in researching, developing, designing, manufacturing, selling, packaging and testing of color filter Hsin-Chu, 87% 87% — TSMC Arizona Corporation (TSMC Arizona) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Phoenix, Arizona, U.S.A. — 100% a), c) VentureTech Alliance Fund II, L.P. (VTAF II) Investing in new start-up Cayman Islands 98% 98% a) VentureTech Alliance Fund III, L.P. (VTAF III) Investing in new start-up Cayman Islands 98% 98% a) TSMC Partners TSMC Development, Inc. (TSMC Development) Investing in companies involved in the manufacturing related business in the semiconductor industry Delaware, U.S.A. 100% 100% — TSMC Technology, Inc. (TSMC Technology) Engineering support activities Delaware, U.S.A. 100% 100% a) TSMC Design Technology Canada Inc. (TSMC Canada) Engineering support activities Ontario, Canada 100% 100% a) InveStar Semiconductor Development Fund, Inc. (ISDF) Investing in new start-up Cayman Islands 97% — a) , e) InveStar Semiconductor Development Fund, Inc. (II) LDC. (ISDF II) Investing in new start-up Cayman Islands 97% — a) , e) TSMC Development WaferTech, LLC (WaferTech) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Washington, U.S.A. 100% 100% — VTAF III Growth Fund Limited (Growth Fund) Investing in new start-up Cayman Islands 100% 100% a) Note a: This is an immaterial subsidiary for which the consolidated financial statements are not audited by the Company’s independent auditors. Note b: TSMC JDC has been established in January 2020. Note c: TSMC Arizona has been established in November 2020. Under the terms of the development agreement entered into between TSMC Arizona and the City of Phoenix in March 2021, the City of Phoenix commits approximately US$205 million toward various public infrastructure projects in the area of the proposed manufacturing facility, conditioned on TSMC Arizona’s achieving a minimum project scale with defined spending and job - Note d: Under the investment agreement entered into with the municipal government of Nanjing, China, the Company will make an investment in Nanjing in the amount of approximately US$3 billion to establish a subsidiary operating a 300mm wafer fab with the capacity of 20,000 12-inch 12-inch Note e: ISDF and ISDF II have completed the liquidation procedures in November 2020.
Foreign Currencies	Foreign Currencies The financial statements of each individual consolidated entity were expressed in the currency which reflected its primary economic environment (functional currency). The functional currency of TSMC In preparing the financial statements of each individual consolidated entity, transactions in currencies other than the entity’s functional currency (foreign currencies) are recognized at the rates of exchange prevailing at the dates of the transactions. At the end of each reporting period, monetary items denominated in foreign currencies are retranslated at the rates prevailing at that date. Such exchange differences are recognized in profit or loss in the year in which they arise. Non-monetary non-monetary non-monetary Non-monetary For the purposes of presenting consolidated financial statements, the assets and liabilities of the Company’s foreign operations are translated into NT$ using exchange rates prevailing at the end of each reporting period. Income and expense items are translated at the average exchange rates for the period. Exchange differences arising, if any, are recognized in other comprehensive income and accumulated in equity (attributed to non-controlling interests as appropriate).
Classification of Current and Noncurrent Assets and Liabilities	Classification of Current and Noncurrent Assets and Liabilities Current assets are assets held for trading purposes and assets expected to be converted to cash, sold or consumed within one year from the end of the reporting period. Current liabilities are obligations incurred for trading purposes and obligations expected to be settled within one year from the end of the reporting period. Assets and liabilities that are not classified as current are noncurrent assets and liabilities, respectively.
Cash Equivalents	Cash Equivalents Cash equivalents, for the purpose of meeting short-term cash commitments, consist of highly liquid time deposits and investments that are readily convertible to known amounts of cash and which are subject to an insignificant risk of changes in value.
Financial Instruments	Financial Instruments Financial assets and liabilities shall be recognized when the Company becomes a party to the contractual provisions of the instruments. Financial assets and liabilities are initially recognized at fair values. Transaction costs that are directly attributable to the acquisition or issue of financial assets and financial liabilities (other than financial assets and financial liabilities at fair value through profit or loss) are added to or deducted from the fair value of the financial assets or financial liabilities, as appropriate, on initial recognition. Transaction costs directly attributable to the acquisition of financial assets or financial liabilities at fair value through profit or loss are recognized immediately in profit or loss.
Financial Assets	Financial Assets The classification of financial assets depends on the nature and purpose of the financial assets and is determined at the time of initial recognition. Regular way purchases or sales of financial assets are recognized and derecognized on a trade date or settlement date basis for which financial assets were classified in the same way, respectively. Regular way purchases or sales are purchases or sales of financial assets that require delivery of assets within the time frame established by regulation or convention in the marketplace. a. Category of financial assets and measurement Financial assets are classified into the following categories: financial assets at FVTPL, investments in debt instruments and equity instruments at FVTOCI, and financial assets at amortized cost. 1) Financial asset at FVTPL For certain financial assets which include debt instruments that do not meet the criteria of amortized cost or FVTOCI, it is mandatorily required to measure them at FVTPL. Any gain or loss arising from remeasurement is recognized in profit or loss. The net gain or loss recognized in profit or loss incorporates any interest earned on the financial asset. 2) Investments in debt instruments at FVTOCI Debt instruments with contractual terms specifying that cash flows are solely payments of principal and interest on the principal amount outstanding, together with objective of collecting contractual cash flows and selling the financial assets, are measured at FVTOCI. Interest income calculated using the effective interest method, foreign exchange gains and losses and impairment gains or losses on investments in debt instruments at FVTOCI are recognized in profit or loss. Other changes in the carrying amount of these debt instruments are recognized in other comprehensive income and will be reclassified to profit or loss when these debt instruments are disposed. 3) Investments in equity instruments at FVTOCI On initial recognition, the Company may irrevocably designate investments in equity investments that is not held for trading as at FVTOCI. Investments in equity instruments at FVTOCI are subsequently measured at fair value with gains and losses arising from changes in fair value recognized in other comprehensive income and accumulated in other equity. Dividends on these investments in equity instruments at FVTOCI are recognized in profit or loss when the Company’s right to receive the dividends is established, unless the Company’s rights clearly represent a recovery of part of the cost of the investment. 4) Measured at amortized cost Cash and cash equivalents, debt instrument investments, notes and accounts receivable (including related parties), other receivables and refundable deposits are measured at amortized cost. Debt instruments with contractual terms specifying that cash flows are solely payments of principal and interest on the principal amount outstanding, together with objective of holding financial assets in order to collect contractual cash flows, are measured at amortized cost. Subsequent to initial recognition, financial assets measured at amortized cost are measured at amortized cost, which equals to carrying amount determined by the effective interest method less any impairment loss. b. Impairment of financial assets At the end of each reporting period, a loss allowance for expected credit loss is recognized for financial assets at amortized cost (including accounts receivable) and for investments in debt instruments that are measured at FVTOCI. The loss allowance for accounts receivable is measured at an amount equal to lifetime expected credit losses. For financial assets at amortized cost and investments in debt instruments that are measured at FVTOCI, when the credit risk on the financial instrument has not increased significantly since initial recognition, a loss allowance is recognized at an amount equal to expected credit loss resulting from possible default events of a financial instrument within 12 months after the reporting date. If, on the other hand, there has been a significant increase in credit risk since initial recognition, a loss allowance is recognized at an amount equal to expected credit loss resulting from all possible default events over the expected life of a financial instrument. The Company recognizes an impairment loss in profit or loss for all financial instruments with a corresponding adjustment to their carrying amount through a loss allowance account, except for investments in debt instruments that are measured at FVTOCI, for which the loss allowance is recognized in other comprehensive income and does not reduce the carrying amount of the financial asset. c. Derecognition of financial assets The Company derecognizes a financial asset only when the contractual rights to the cash flows from the financial asset expire, or when it transfers the financial asset and substantially all the risks and rewards of ownership of the financial asset to another entity. On derecognition of a financial asset at amortized cost in its entirety, the difference between the asset’s carrying amount and the sum of the consideration received and receivable is recognized in profit or loss. On derecognition of an investment in a debt instrument at FVTOCI, the difference between the asset’s carrying amount and the sum of the consideration received and receivable and the cumulative gain or loss that had been recognized in other comprehensive income is recognized in profit or loss. However, on derecognition of an investment in an equity instrument at FVTOCI, the cumulative gain or loss that had been recognized in other comprehensive income is transferred directly to retained earnings, without recycling through profit or loss.
Financial Liabilities and Equity Instruments	Financial Liabilities and Equity Instruments Classification as debt or equity Debt and equity instruments issued by the Company are classified as either financial liabilities or as equity in accordance with the substance of the contractual arrangements and the definitions of a financial liability and an equity instrument. Equity instruments An equity instrument is any contract that evidences a residual interest in the assets of an entity after deducting all of its liabilities. Equity instruments issued by the Company are recognized at the proceeds received, net of direct issue costs. Financial liabilities Financial liabilities are subsequently measured either at amortized cost using effective interest method or at FVTPL. Financial liabilities are classified as at fair value through profit or loss when the financial liability is either held for trading or is designated as at fair value through profit or loss. Financial liabilities at fair value through profit or loss are stated at fair value, with any gains or losses arising on remeasurement recognized in profit or loss. Financial liabilities other than those held for trading purposes and designated as at FVTPL are subsequently measured at amortized cost at the end of each reporting period. Derecognition of financial liabilities The Company derecognizes financial liabilities when, and only when, the Company’s obligations are discharged, cancelled or they expire. The difference between the carrying amount of the financial liability derecognized and the consideration paid and payable is recognized in profit or loss.
Derivative Financial Instruments	Derivative Financial Instruments
Hedge Accounting	Hedge Accounting a. Fair value hedge The Company designates certain hedging instruments, such as interest rate futures contracts, to partially hedge against the fair value change caused by interest rates fluctuation in the Company’s fixed income investments. Changes in the fair value of hedging instrument that are designated and qualify as fair value hedges are recognized in profit or loss immediately, together with any changes in the fair value of the hedged items that are attributable to the hedged risk. b. Cash flow hedge The Company designates certain hedging instruments, such as forward exchange contracts and foreign currency deposits, to partially hedge its foreign exchange rate risks associated with certain highly probable forecast transactions (capital expenditures). The effective portion of changes in the fair value of hedging instruments is recognized in other comprehensive income. When the forecast transactions actually take place, the associated gains or losses that were recognized in other comprehensive income are removed from equity and included in the initial cost of the hedged items. The gains or losses from hedging instruments relating to the ineffective portion are recognized immediately in profit or loss. The Company prospectively discontinues hedge accounting only when the hedging relationship ceases to meet the qualifying criteria; for instance, when the hedging instrument expires or is sold, terminated or exercised.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value. Inventories are recorded at standard cost and adjusted to approximate weighted-average cost at the end of the reporting period. Net realizable value represents the estimated selling price of inventories less all estimated costs of completion and costs necessary to make the sale.
Investments Accounted for Using Equity Method	Investments Accounted for Using Equity Method Investments accounted for using the equity method are investments in associates. An associate is an entity over which the Company has significant influence and that is neither a subsidiary nor a joint venture. Significant influence is the power to participate in the financial and operating policy decisions of the investee but is not control or joint control over those policies. The operating results and assets and liabilities of associates are incorporated in these consolidated financial statements using the equity method of accounting. Under the equity method, an investment in an associate is initially recognized in the consolidated statements of financial position at cost and adjusted thereafter to recognize the Company’s share of profit or loss and other comprehensive income of the associate as well as the distribution received. The Company also recognizes its share in the changes in the equities of associates. Any excess of the cost of acquisition over the Company’s share of the net fair value of the identifiable assets, liabilities and contingent liabilities of an associate recognized at the date of acquisition is recognized as goodwill, which is included within the carrying amount of the investment. Any excess of the Company’s share of the net fair value of the identifiable assets, liabilities and contingent liabilities over the cost of acquisition, after reassessment, is recognized immediately in profit or loss. When necessary, the entire carrying amount of the investment (including goodwill) is tested for impairment as a single asset by comparing its recoverable amount (higher of value in use and fair value less costs to sell) with its carrying amount. Any impairment loss recognized forms part of the carrying amount of the investment. Any reversal of that impairment loss is recognized to the extent that the recoverable amount of the investment subsequently increases. When the Company subscribes to additional shares in an associate at a percentage different from its existing ownership percentage, the resulting carrying amount of the investment differs from the amount of the Company’s proportionate interest in the net assets of the associate. The Company records such a difference as an adjustment to investments with the corresponding amount charged or credited to capital surplus. If the Company’s ownership interest is reduced due to the additional subscription to the shares of associate by other investors, the proportionate amount of the gains or losses previously recognized in other comprehensive income in relation to that associate shall be reclassified to profit or loss on the same basis as would be required if the associate had directly disposed of the related assets or liabilities. When a consolidated entity transacts with an associate, profits and losses resulting from the transactions with the associate are recognized in the Company’s consolidated financial statements only to the extent of interests in the associate that are not owned by the Company.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are measured at cost less accumulated depreciation and accumulated impairment. Costs include any incremental costs that are directly attributable to the construction or acquisition of the item of property, plant and equipment. Property, plant and equipment in the course of construction for production, supply or administrative purposes are carried at cost, less any recognized impairment loss. Such assets are classified to the appropriate categories of property, plant and equipment when completed and ready for intended use. Depreciation of these assets, on the same basis as other identical categories of property, plant and equipment, commences when the assets are available for their intended use. Depreciation is recognized so as to write off the cost of the assets less their residual values over their useful lives, and it is computed using the straight-line method mainly over the following estimated useful lives: land improvements—20 years; buildings (assets used by the Company and assets subject to operating leases)- 10 to 20 years; machinery and equipment (assets used by the Company and assets subject to operating leases) - 5 years; and office equipment—5 years. The estimated useful lives, residual values and depreciation method are reviewed at the end of each reporting period, with the effect of any changes in estimates accounted for on a prospective basis. Land is not depreciated. An item of property, plant and equipment is derecognized upon disposal or when no future economic benefits are expected to arise from the continued use of the assets. Any gain or loss arising on the disposal or retirement of an item of property, plant and equipment is determined as the difference between the sales proceeds and the carrying amount of the asset and is recognized in profit or loss.
Leases	Leases 2018 Leases are classified as finance lease whenever the terms of the lease transfer substantially all the risks and rewards of ownership to the lessee. All other leases are classified as operating leases. The Company as lessor Rental income from operating leases is recognized on a straight-line basis over the term of the lease. The Company as lessee Operating lease payments are recognized as an expense on a straight-line basis over the lease term. 2019 and 2020 For a contract that contains a lease component and non-lease non-lease The Company as lessor Rental income from operating lease is recognized on a straight-line basis over the term of the lease. The Company as lessee Except for payments for low-value right-of-use Right-of-use right-of-use Right-of-use Right-of-use right-of-use right-of-use right-of-use Lease liabilities are measured at the present value of the lease payments. Lease payments comprise fixed payments, variable lease payments which depend on an index or a rate and the exercise price of a purchase option if the Company is reasonably certain to exercise that option. The lease payments are discounted using the lessee’s incremental borrowing rates. Subsequently, lease liabilities are measured at amortized cost using the effective interest method, with interest expense recognized over the lease terms. When there is a change in a lease term, a change in future lease payments resulting from a change in an index or a rate used to determine those payments, or a change in the assessment of an option to purchase an underlying asset, the Company remeasures the lease liabilities with a corresponding adjustment to the right-of-use Variable lease payments that do not depend on an index or a rate are recognized as expenses in the periods in which they are incurred.
Intangible Assets	Intangible Assets Goodwill Goodwill arising on an acquisition of a business is carried at cost as established at the date of acquisition of the business less accumulated impairment losses, if any. Other intangible assets Other separately acquired intangible assets with finite useful lives are carried at cost less accumulated amortization and accumulated impairment losses. Amortization is recognized using the straight-line method over the following estimated useful lives: Technology license fees - the estimated life of the technology or the term of the technology transfer contract; software and system design costs - 3 years or contract period; patent and others - the economic life or contract period. The estimated useful life and amortization method are reviewed at the end of each reporting period, with the effect of any changes in estimate being accounted for on a prospective basis.
Impairment of Tangible Assets, Right-of-use Assets and Intangible Assets	Impairment of Tangible Assets, Right-of-use Goodwill Goodwill is not amortized and instead is tested for impairment annually, or more frequently when there is an indication that the cash generating unit may be impaired. For the purpose of impairment testing, goodwill is allocated to each of the Company’s cash-generating units or groups of cash-generating units that are expected to benefit from the synergies of the combination. If the recoverable amount of a cash-generating unit is less than its carrying amount, the difference is allocated first to reduce the carrying amount of any goodwill allocated to such cash generating unit and then to the other assets of the cash generating unit pro rata based on the carrying amount of each asset in the cash generating unit. Any impairment loss for goodwill is recognized directly in profit or loss. An impairment loss recognized for goodwill is not reversed in subsequent periods. Tangible assets, right-of-use At the end of each reporting period, the Company reviews the carrying amounts of its tangible assets (property, plant and equipment), right-of-use Recoverable amount is the higher of fair value less costs to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax If the recoverable amount of an asset or cash-generating unit is estimated to be less than its carrying amount, the carrying amount of the asset or cash-generating unit is reduced to its recoverable amount. An impairment loss is recognized immediately in profit or loss. When an impairment loss subsequently reverses, the carrying amount of the asset or a cash-generating unit is increased to the revised estimate of its recoverable amount, but the increased carrying amount does not exceed the carrying amount that would have been determined had no impairment loss been recognized for the asset or cash-generating unit in prior years. A reversal of an impairment loss is recognized immediately in profit or loss.
Guarantee Deposit	Guarantee Deposit Guarantee deposit mainly consists of cash received under deposit agreements with customers to ensure they have access to the Company’s specified capacity. Cash received from customers is recorded as guarantee deposit upon receipt. Guarantee deposits are refunded to customers when terms and conditions set forth in the deposit agreements have been satisfied.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when performance obligations are satisfied. The performance obligations are satisfied when customers obtain control of the promised goods, which is generally when the goods are delivered to the customers’ specified locations. Revenue from sale of goods is measured at the fair value of the consideration received or receivable. Revenue is reduced for estimated customer returns, rebates and other similar allowances. Estimated sales returns and other allowances is generally made and adjusted based on historical experience and the consideration of varying contractual terms to recognize refund liabilities, which is classified under accrued expenses and other current liabilities. In principle, payment term granted to customers is due 30 days from the invoice date or 30 days from the end of the month of when the invoice is issued. Due to the short term nature of the receivables from sale of goods with the immaterial discounted effect, the Company measures them at the original invoice amounts without discounting.
Employee Benefits	Employee Benefits Short-term employee benefits Liabilities recognized in respect of short-term employee benefits are measured at the undiscounted amount of the benefits expected to be paid in exchange for service rendered by employees. Retirement benefits For defined contribution retirement benefit plans, payments to the benefit plan are recognized as an expense when the employees have rendered service entitling them to the contribution. For defined benefit retirement benefit plans, the cost of providing benefit is recognized based on actuarial calculations. Defined benefit costs (including service cost, net interest and remeasurement) under the defined benefit retirement benefit plans are determined using the Projected Unit Credit Method. Service cost (including current service cost), and net interest on the net defined benefit liability (asset) are recognized as employee benefits expense in the period they occur. Remeasurement, comprising actuarial gains and losses and the return on plan assets (excluding interest), is recognized in other comprehensive income in the period in which they occur. Remeasurement recognized in other comprehensive income is reflected immediately in retained earnings and will not be reclassified to profit or loss. Net defined benefit liability represents the actual deficit in the Company’s defined benefit plan.
Taxation	Taxation Income tax expense represents the sum of the tax currently payable and deferred tax. Current tax Income tax on unappropriated earnings (excluding earnings from foreign consolidated subsidiaries) is expensed in the year the earnings arise and adjusted to the extent that distributions are approved by the shareholders in the following year. Adjustments of prior years’ tax liabilities are added to or deducted from the current year’s tax provision. Deferred tax Deferred tax is recognized on temporary differences between the carrying amounts of assets and liabilities in the consolidated financial statements and the corresponding tax bases used in the computation of taxable profit. Deferred tax liabilities are generally recognized for all taxable temporary differences. Deferred tax assets are generally recognized for all deductible temporary differences, net operating loss carryforwards and tax credits for research and development expenses to the extent that it is probable that taxable profits will be available against which those deductible temporary differences can be utilized. Deferred tax liabilities are recognized for taxable temporary differences associated with investments in subsidiaries and associates, except where the Company is able to control the reversal of the temporary difference and it is probable that the temporary difference will not reverse in the foreseeable future. Deferred tax assets arising from deductible temporary differences associated with such investments are only recognized to the extent that it is probable that there will be sufficient taxable profits against which to utilize the benefits of the temporary differences and they are expected to reverse in the foreseeable future. The carrying amount of deferred tax assets is reviewed at the end of each reporting period and reduced to the extent that it is no longer probable that sufficient taxable profits will be available to allow all or part of the deferred tax asset to be recovered. The deferred tax assets which originally not recognized is also reviewed at the end of each reporting period and recognized to the extent that it is probable that sufficient taxable profits will be available to allow all or part of the deferred tax asset to be recovered. Deferred tax liabilities and assets are measured at the tax rates that are expected to apply in the year in which the liability is settled or the asset is realized, based on tax rates (and tax laws) that have been enacted or substantively enacted by the end of the reporting period. The measurement of deferred tax liabilities and assets reflects the tax consequences that would follow from the manner in which the Company expects, at the end of the reporting period, to recover or settle the carrying amount of its assets and liabilities. Current and deferred tax for the year Current and deferred tax are recognized in profit or loss, except when they relate to items that are recognized in other comprehensive income or directly in equity, in which case, the current and deferred tax are also recognized in other comprehensive income or directly in equity, respectively.
Government Grants	Government Grants Government grants are not recognized until there is reasonable assurance that the Company will comply with the conditions attaching to them and that the grants will be received. Government grants whose primary condition is that the Company should purchase, construct or otherwise acquire noncurrent assets (mainly including land use right and depreciable assets) are recognized as a deduction from the carrying amount of the related assets and recognized as a reduced depreciation or amortization charge in profit or loss over the contract period or useful lives of the related assets. Government grants that are receivables as compensation for expenses already incurred are deducted from incurred expenses in the period in which they become receivables.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Detail Information of Subsidiaries	The detail information of the subsidiaries at the end of reporting period was as follows: Percentage of Ownership Name of Investor Name of Investee Main Businesses and Products Establishment and Operating December 31, 2019 December 31, 2020 Note TSMC TSMC North America Selling and marketing of integrated circuits and other semiconductor devices San Jose, California, U.S.A. 100% 100% — TSMC Europe B.V. (TSMC Europe) Customer service and supporting activities Amsterdam, the Netherlands 100% 100% a) TSMC Japan Limited (TSMC Japan) Customer service and supporting activities Yokohama, Japan 100% 100% a) TSMC Design Technology Japan, Inc. (TSMC JDC) Engineering support activities Yokohama, Japan — 100% a), b) TSMC Korea Limited (TSMC Korea) Customer service and supporting activities Seoul, Korea 100% 100% a) TSMC TSMC Partners, Ltd. (TSMC Partners) Investing in companies involved in the design, manufacture, and other related business in the semiconductor industry and other investment activities Tortola, British Virgin Islands 100% 100% a) TSMC Global, Ltd. (TSMC Global) Investment activities Tortola, British Virgin Islands 100% 100% — TSMC China Company Limited (TSMC China) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Shanghai, China 100% 100% — TSMC Nanjing Company Limited (TSMC Nanjing) Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices Nanjing, China 100% 100% d) VisEra Technologies Company Ltd. (VisEra Tech) Engaged in manufacturing electronic spare parts and in researching, developing, designing, manufacturing, selling, packaging and testing of color filter Hsin-Chu, 87% 87% — TSMC Arizona Corporation (TSMC Arizona) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Phoenix, Arizona, U.S.A. — 100% a), c) VentureTech Alliance Fund II, L.P. (VTAF II) Investing in new start-up Cayman Islands 98% 98% a) VentureTech Alliance Fund III, L.P. (VTAF III) Investing in new start-up Cayman Islands 98% 98% a) TSMC Partners TSMC Development, Inc. (TSMC Development) Investing in companies involved in the manufacturing related business in the semiconductor industry Delaware, U.S.A. 100% 100% — TSMC Technology, Inc. (TSMC Technology) Engineering support activities Delaware, U.S.A. 100% 100% a) TSMC Design Technology Canada Inc. (TSMC Canada) Engineering support activities Ontario, Canada 100% 100% a) InveStar Semiconductor Development Fund, Inc. (ISDF) Investing in new start-up Cayman Islands 97% — a) , e) InveStar Semiconductor Development Fund, Inc. (II) LDC. (ISDF II) Investing in new start-up Cayman Islands 97% — a) , e) TSMC Development WaferTech, LLC (WaferTech) Manufacturing, selling and testing of integrated circuits and other semiconductor devices Washington, U.S.A. 100% 100% — VTAF III Growth Fund Limited (Growth Fund) Investing in new start-up Cayman Islands 100% 100% a) Note a: This is an immaterial subsidiary for which the consolidated financial statements are not audited by the Company’s independent auditors. Note b: TSMC JDC has been established in January 2020. Note c: TSMC Arizona has been established in November 2020. Under the terms of the development agreement entered into between TSMC Arizona and the City of Phoenix in March 2021, the City of Phoenix commits approximately US$205 million toward various public infrastructure projects in the area of the proposed manufacturing facility, conditioned on TSMC Arizona’s achieving a minimum project scale with defined spending and job - Note d: Under the investment agreement entered into with the municipal government of Nanjing, China, the Company will make an investment in Nanjing in the amount of approximately US$3 billion to establish a subsidiary operating a 300mm wafer fab with the capacity of 20,000 12-inch 12-inch Note e: ISDF and ISDF II have completed the liquidation procedures in November 2020.

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Cash and Cash Equivalents	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Cash and deposits in banks $ 452,734.4 $ 653,580.6 Government bonds 2,188.1 3,716.1 Repurchase agreements — 1,750.4 Commercial paper 476.8 1,123.5 $ 455,399.3 $ 660,170.6

Financial Assets and Liabilit_2

Financial Assets and Liabilities at Fair Value through Profit or Loss (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Summary of Financial Assets and Liabilities at Fair Value through Profit or Loss	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets Mandatorily measured at FVTPL Forward exchange contracts $ 162.1 $ 2,259.4 Convertible bonds 123.8 — Agency mortgage-backed securities 40.9 — $ 326.8 $ 2,259.4 Financial liabilities Held for trading Forward exchange contracts $ 982.3 $ 94.1
Forward exchange contracts [member]
Statement [LineItems]
Outstanding Derivative Contracts for which Hedge Accounting Treatment is not Applied	Outstanding forward exchange contracts consisted of the following: Maturity Date Contract Amount December 31, 2019 Sell NT$ January 2020 to June 2020 NT$108,428.0 Sell JPY January 2020 to February 2020 JPY57,471.6 Sell US$ January 2020 to March 2020 US$529.2 December 31, 2020 Sell NT$ January 2021 to March 2021 NT$144,698.0 Sell US$ January 2021 to March 2021 US$1,176.9

Financial Assets at Fair Valu_2

Financial Assets at Fair Value Through Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Financial Assets at Fair Value through Other Comprehensive Income	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Investments in debt instruments at FVTOCI Corporate bonds $ 51,790.0 $ 56,593.6 Agency bonds/Agency mortgage-backed securities 51,966.5 43,977.1 Government bonds 12,824.2 13,459.5 Asset-backed securities 10,815.9 8,368.3 127,396.6 122,398.5 Investments in equity instruments at FVTOCI Non-publicly 4,124.3 4,514.9 Publicly traded stocks — 50.0 4,124.3 4,564.9 $ 131,520.9 $ 126,963.4 Current $ 127,396.6 $ 122,448.5 Noncurrent 4,124.3 4,514.9 $ 131,520.9 $ 126,963.4

Financial Assets at Amortized_2

Financial Assets at Amortized Cost (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Schedule of Financial Assets at Amortized Cost	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Corporate bonds $ 7,651.7 $ 10,977.3 Less: Allowance for impairment loss (2.9 ) (7.1 ) $ 7,648.8 $ 10,970.2 Current $ 299.9 $ 6,598.0 Noncurrent 7,348.9 4,372.2 $ 7,648.8 $ 10,970.2

Hedging Financial Instruments (

Hedging Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Summary of hedging financial instruments	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets- current Fair value hedges Interest rate futures contracts $ 22.4 $ 0.1 Cash flow hedges Forward exchange contracts 3.5 — $ 25.9 $ 0.1 Financial liabilities- current Fair value hedges Interest rate futures contracts $ — $ 1.2 Cash flow hedges Forward exchange contracts 1.8 — $ 1.8 $ 1.2
Interest rate risk [member]
Statement [LineItems]
Summary of Information Related to Hedged Items	The following tables summarize the information relating to the hedges of interest rate risk. December 31, 2019 Hedging Instruments Contract Amount (US$ in Millions) Maturity Interest rate futures contracts - US Treasury bonds US$122.2 March 2020 Hedged Items Asset Carrying Amount Accumulated Amount of Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets at FVTOCI $ 7,364.7 $ (22.4) December 31, 2020 Hedging Instruments Contract Amount (US$ in Millions) Maturity Interest rate futures contracts - US Treasury bonds US$88.7 March 2021 Hedged Items Asset Carrying Amount Accumulated Amount of Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets at FVTOCI $ 6,198.7 $ 1.1 The effect for the years ended December 31, 2018, 2019 and 2020 is d e Hedging Instruments/Hedged Items Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Hedging Instruments Interest rate futures contracts - US Treasury bonds $ 11.5 $ (164.7 ) $ (353.6 ) Hedged Items Financial assets at FVTOCI (13.8 ) 177.8 353.6 $ (2.3 ) $ 13.1 $ —
Foreign currency risk [member]
Statement [LineItems]
Summary of Information Related to Hedged Items	The following tables summarize the information relating to the hedges for foreign currency risk. December 31, 2019 Hedging Instruments Contract Amount (In Millions) Maturity Balance in Other Equity NT$ (In Millions) Forward exchange contracts Sell NT$ 1,342.4 January 2020 $ (3.8 )
Cash flow hedges [member]
Statement [LineItems]
Summary of Hedging Derivative Financial Instruments	The effect for the years ended December 31, 2018, 2019 an d Hedging Instruments/Hedged Items Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Hedging Instruments Forward exchange contracts $ 34.6 $ (109.6 ) $ 24.1 Foreign currency deposits 6.4 — — $ 41.0 $ (109.6 ) $ 24.1 Hedged Items Forecast transaction (capital expenditures) $ (41.0 ) $ 109.6 $ (24.1 )

Notes and Accounts Receivable_2

Notes and Accounts Receivable, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Summary of Notes and Accounts Receivable, Net	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) At amortized cost Notes and accounts receivable $ 135,978.0 $ 142,771.6 Less: Loss allowance (325.3 ) (246.6 ) 135,652.7 142,525.0 At FVTOCI 3,255.9 2,955.3 $ 138,908.6 $ 145,480.3
Movements of Allowance for Doubtful Receivables	Movements of the loss allowance for accounts receivable Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 227.0 $ 7.3 $ 325.3 Provision (Reversal) (219.7 ) 318.2 (78.5 ) Effect of exchange rate changes — (0.2 ) (0.2 ) Balance, end of year $ 7.3 $ 325.3 $ 246.6
Trade accounts and notes receivable [member]
Statement [LineItems]
Aging Analysis of Notes and Accounts Receivable, Net	Aging analysis of notes and accounts receivable December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Not past due $ 126,134.8 $ 140,933.6 Past due Past due within 30 days 13,082.1 4,784.4 Past due 31-60 12.8 8.7 Past due 61-120 1.0 0.1 Past due over 121 days 3.2 0.1 Less: Loss allowance (325.3 ) (246.6 ) $ 138,908.6 $ 145,480.3

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Inventories	December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Finished goods $ 8,924.5 $ 21,705.6 Work in process 51,969.1 91,672.9 Raw materials 16,552.3 14,716.0 Supplies and spare parts 5,535.3 9,258.9 $ 82,981.2 $ 137,353.4
Inventory write downs	Write-down of inventories to net realizable v a Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Inventory losses (reversal of write-down of inventories) $ 1,259.5 $ (1,983.0 ) $ 3,664.5 The aforementioned inventory losses (reversal of write-down of inventories) for the years ended December 31, 2018 and 2019 excluded computer virus outbreak losses and wafer contamination losses. Please refer to related losses in Note 37.

Investments Accounted for Usi_2

Investments Accounted for Using Equity Method (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Investments in Associates	Associates consisted of the following: Place of Incorporation and Operation Carrying Amount % of Ownership and Voting Rights Name of Associate Principal Activities December 31, December 31, December 31, December 31, NT$ NT$ (In Millions) (In Millions) Vanguard International Semiconductor Corporation (VIS) Manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing and design service of masks Hsinchu, Taiwan $ 8,960.5 $ 8,964.1 28% 28% Systems on Silicon Manufacturing Company Pte Ltd. (SSMC) Manufacturing and selling of integrated circuits and other semiconductor devices Singapore 6,502.2 5,900.2 39% 39% Xintec Inc. (Xintec) Wafer level chip size packaging and wafer level post passivation interconnection service Taoyuan, Taiwan 1,842.8 2,522.3 41% 41% Global Unichip Corporation (GUC) Researching, developing, manufacturing, testing and marketing of integrated circuits Hsinchu, Taiwan 1,274.8 1,315.4 35% 35% Mutual-Pak Manufacturing of electronic parts, wholesaling and retailing of electronic materials, and researching, developing and testing of RFID New Taipei, Taiwan 38.5 28.2 28% 28% $ 18,618.8 $ 18,730.2
Summary of Market Prices of Investments Accounted for Using Equity Method in Publicly Traded Stocks Calculated by Closing Price at End of Reporting Period	December 31, 2019 December 31, 2020 NT$ NT$ Name of Associate (In Millions) (In Millions) VIS $ 36,812.9 $ 53,849.9 Xintec $ 8,958.2 $ 20,420.2 GUC $ 11,251.8 $ 15,827.2

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure of detailed information about property, plant and equipment [line items]
Summary of Property, Plant and Equipment	Land and Land Buildings Machinery and Office Equipment Equipment under Total NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2018 $ 3,983.2 $ 379,134.6 $ 2,487,752.3 $ 42,391.5 $ 167,353.5 $ 3,080,615.1 Additions — 40,396.4 247,042.3 6,773.4 5,812.3 300,024.4 Disposals or retirements — (410.9 ) (5,972.5 ) (790.8 ) — (7,174.2 ) Effect of exchange rate changes 28.2 (405.8 ) (61.9 ) 8.1 (254.8 ) (686.2 ) Balance at December 31, 2018 $ 4,011.4 $ 418,714.3 $ 2,728,760.2 $ 48,382.2 $ 172,911.0 $ 3,372,779.1 Accumulated depreciation and impairment Balance at January 1, 2018 $ 510.5 $ 194,446.5 $ 1,795,448.9 $ 27,666.9 $ — $ 2,018,072.8 Additions 20.9 24,293.4 258,195.3 5,615.3 — 288,124.9 Disposals or retirements — (399.0 ) (4,773.6 ) (790.0 ) — (5,962.6 ) Impairment — — 423.5 — — 423.5 Effect of exchange rate changes 19.2 33.2 (15.1 ) 32.9 — 70.2 Balance at December 31, 2018 $ 550.6 $ 218,374.1 $ 2,049,279.0 $ 32,525.1 $ — $ 2,300,728.8 Carrying amounts at December 31, 2018 $ 3,460.8 $ 200,340.2 $ 679,481.2 $ 15,857.1 $ 172,911.0 $ 1,072,050.3
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Summary of maturity analysis of operating lease payments receivable	The maturity ana l December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Year 1 $ 18.4 $ 149.1 Year 2 17.0 17.0 Year 3 17.0 — $ 52.4 $ 166.1
Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Summary of Property, Plant and Equipment	Land and Land Buildings Machinery and Office Equipment Equipment under Total NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Cost Balance at January 1, 2019 $ 4,011.4 $ 418,151.7 $ 2,728,760.2 $ 48,382.2 $ 172,911.0 $ 3,372,216.5 Additions — 21,448.5 179,798.4 7,415.0 355,621.1 564,283.0 Disposals or retirements — (159.0 ) (17,381.6 ) (1,043.3 ) — (18,583.9 ) Transfers from right-of-use — — 619.8 — — 619.8 Effect of disposal of subsidiary — — — (0.5 ) — (0.5 ) Effect of exchange rate changes (19.6 ) (1,366.2 ) (5,173.8 ) (142.0 ) (237.0 ) (6,938.6 ) Balance at December 31, 2019 $ 3,991.8 $ 438,075.0 $ 2,886,623.0 $ 54,611.4 $ 528,295.1 $ 3,911,596.3 Accumulated depreciation and impairment Balance at January 1, 2019 $ 550.6 $ 217,899.2 $ 2,049,279.0 $ 32,525.1 $ — $ 2,300,253.9 Additions 1.6 26,026.6 246,724.2 6,012.5 — 278,764.9 Disposals or retirements — (144.4 ) (12,880.8 ) (1,042.1 ) — (14,067.3 ) Transfers from right-of-use — — 20.7 — — 20.7 Reversal of impairment — — (301.4 ) — — (301.4 ) Effect of disposal of subsidiary — — — (0.5 ) — (0.5 ) Effect of exchange rate changes (13.5 ) (722.1 ) (4,575.7 ) (76.6 ) — (5,387.9 ) Balance at December 31, 2019 $ 538.7 $ 243,059.3 $ 2,278,266.0 $ 37,418.4 $ — $ 2,559,282.4 Carrying amounts at December 31, 2019 $ 3,453.1 $ 195,015.7 $ 608,357.0 $ 17,193.0 $ 528,295.1 $ 1,352,313.9 Cost Balance at January 1, 2020 $ 3,991.8 $ 438,075.0 $ 2,886,623.0 $ 54,611.4 $ 528,295.1 $ 3,911,596.3 Additions (deductions) — 84,882.5 729,943.3 15,112.9 (304,218.0 ) 525,720.7 Disposals or retirements — (41.5 ) (6,397.3 ) (734.1 ) — (7,172.9 ) Transfers from assets subject to operating leases — 23.1 — — — 23.1 Transfers to assets subject to operating leases — — (1,199.0 ) — — (1,199.0 ) Effect of exchange rate changes (49.2 ) (491.7 ) (1,964.3 ) (127.5 ) (111.7 ) (2,744.4 ) Balance at December 31, 2020 $ 3,942.6 $ 522,447.4 $ 3,607,005.7 $ 68,862.7 $ 223,965.4 $ 4,426,223.8 Accumulated depreciation and impairment Balance at January 1, 2020 $ 538.7 $ 243,059.3 $ 2,278,266.0 $ 37,418.4 $ — $ 2,559,282.4 Additions 1.5 29,209.1 285,393.6 7,216.9 — 321,821.1 Disposals or retirements — (27.9 ) (6,012.9 ) (732.4 ) — (6,773.2 ) Transfers from assets subject to operating leases — 8.2 — — — 8.2 Transfers to assets subject to operating leases — — (202.6 ) — — (202.6 ) Impairment — — 10.2 — — 10.2 Effect of exchange rate changes (34.1 ) (449.2 ) (1,924.3 ) (100.6 ) — (2,508.2 ) Balance at December 31, 2020 $ 506.1 $ 271,799.5 $ 2,555,530.0 $ 43,802.3 $ — $ 2,871,637.9 Carrying amounts at December 31, 2020 $ 3,436.5 $ 250,647.9 $ 1,051,475.7 $ 25,060.4 $ 223,965.4 $ 1,554,585.9
Property, plant and equipment subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Summary of Property, Plant and Equipment	Buildings Machinery and Total NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2019 $ 562.6 $ — $ 562.6 Balance at December 31, 2019 $ 562.6 $ — $ 562.6 Accumulated depreciation Balance at January 1, 2019 $ 474.9 $ — $ 474.9 Additions 24.2 — 24.2 Balance at December 31, 2019 $ 499.1 $ — $ 499.1 Carrying amounts at December 31, 2019 $ 63.5 $ — $ 63.5 Cost Balance at January 1, 2020 $ 562.6 $ — $ 562.6 Disposals or retirements (311.9 ) — (311.9 ) Transfers to assets used by the Company (23.1 ) — (23.1 ) Transfers from assets used by the Company — 1,199.0 1,199.0 Balance at December 31, 2020 $ 227.6 $ 1,199.0 $ 1,426.6 Accumulated depreciation Balance at January 1, 2020 $ 499.1 $ — $ 499.1 Additions 16.3 19.4 35.7 Disposals or retirements (305.8 ) — (305.8 ) Transfers to assets used by the Company (8.2 ) — (8.2 ) Transfers from assets used by the Company — 202.6 202.6 Balance at December 31, 2020 $ 201.4 $ 222.0 $ 423.4 Carrying amounts at December 31, 2020 $ 26.2 $ 977.0 $ 1,003.2
Property plant and equipment including subject and not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Summary of Property, Plant and Equipment	December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Assets used by the Company $ 1,352,313.9 $ 1,554,585.9 Assets subject to operating leases 63.5 1,003.2 $ 1,352,377.4 $ 1,555,589.1

Lease Arrangements (Tables)

Lease Arrangements (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Minimum Lease Payments Expensed	The Company expensed the lease payments as follows: Year Ended NT$ (In Millions) Minimum lease payments $ 4,243.1
Future Minimum Lease Payments under Non-cancellable Operating Leases	Future minimum lease payments under the above non-cancellable December 31, NT$ (In Millions) Not later than 1 year $ 5,824.1 Later than 1 year and not later than 5 years 5,834.9 Later than 5 years 9,190.6 $ 20,849.6
Right-of-use assets	a. Right-of-use December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Carrying amounts Land $ 14,064.0 $ 25,141.9 Buildings 2,351.8 2,544.8 Machinery and equipment 775.8 — Office equipment 40.8 41.8 $ 17,232.4 $ 27,728.5 Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Additions to right-of-use $ 1,033.0 $ 13,481.2 Depreciation of right-of-use Land $ 957.1 $ 1,312.9 Buildings 458.8 569.5 Machinery and equipment 1,184.4 775.8 Office equipment 22.4 23.4 $ 2,622.7 $ 2,681.6 Income from subleasing right-of-use $ 55.0 $ 79.6
Lease liabilities	b. Lease liabilities December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Carrying amounts Current portion (classified under accrued expenses and other current liabilities) $ 2,275.1 $ 1,828.0 Noncurrent portion 15,041.8 20,560.6 $ 17,316.9 $ 22,388.6
Ranges of discount rates for lease liabilities	Ranges of discount rates for lease liabilities are as follows: December 31, 2019 December 31, 2020 Land 0.67%-2.14% 0.48%-2.14% Buildings 0.67%-3.88% 0.54%-3.88% Machinery and equipment 3.24% — Office equipment 0.64%-3.88% 0.28%-3.88%
Maturity analysis of lease payments receivable	The maturity analysis of lease payments receivable under operating subleases is as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Year 1 $ 58.6 $ 144.1 Year 2 1.9 — $ 60.5 $ 144.1
Other lease information	e.   Other lease information Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Expenses relating to short-term leases $ 5,007.1 $ 3,153.5 Expenses relating to low-value $ 0.5 $ 0.3 Expenses relating to variable lease payments not included in the measurement of lease liabilities $ 195.1 $ 257.0 Years Ended December 31 2019 2020 NT$ NT$ (In Millions) (In Millions) Total cash outflow for leases $ 7,724.4 $ 6,354.6

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Intangible Assets	Goodwill Technology Software and Patent and Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Cost Balance at January 1, 2018 $ 5,648.7 $ 10,443.3 $ 25,186.3 $ 5,716.0 $ 46,994.3 Additions — 533.7 4,601.9 1,969.4 7,105.0 Disposals or retirements — — (186.7 ) (31.2 ) (217.9 ) Effect of exchange rate changes 146.8 (2.5 ) (6.9 ) 2.1 139.5 Balance at December 31, 2018 $ 5,795.5 $ 10,974.5 $ 29,594.6 $ 7,656.3 $ 54,020.9 Accumulated amortization and impairment Balance at January 1, 2018 $ — $ 7,694.9 $ 20,376.7 $ 4,747.5 $ 32,819.1 Additions — 1,063.6 2,835.3 522.5 4,421.4 Disposals or retirements — — (186.6 ) (31.2 ) (217.8 ) Effect of exchange rate changes — (2.5 ) (1.7 ) 0.3 (3.9 ) Balance at December 31, 2018 $ — $ 8,756.0 $ 23,023.7 $ 5,239.1 $ 37,018.8 Carrying amounts at December 31, 2018 $ 5,795.5 $ 2,218.5 $ 6,570.9 $ 2,417.2 $ 17,002.1 Cost Balance at January 1, 2019 $ 5,795.5 $ 10,974.5 $ 29,594.6 $ 7,656.3 $ 54,020.9 Additions — 4,879.6 3,710.4 647.8 9,237.8 Disposals or retirements — — (260.9 ) — (260.9 ) Effect of exchange rate changes (102.1 ) 0.9 (20.1 ) (1.2 ) (122.5 ) Balance at December 31, 2019 $ 5,693.4 $ 15,855.0 $ 33,024.0 $ 8,302.9 $ 62,875.3 Accumulated amortization and impairment Balance at January 1, 2019 $ — $ 8,756.0 $ 23,023.7 $ 5,239.1 $ 37,018.8 Additions — 1,066.9 3,747.3 658.2 5,472.4 Disposals or retirements — — (258.6 ) — (258.6 ) Effect of exchange rate changes — 0.9 (10.3 ) (0.9 ) (10.3 ) Balance at December 31, 2019 $ — $ 9,823.8 $ 26,502.1 $ 5,896.4 $ 42,222.3 Carrying amounts at December 31, 2019 $ 5,693.4 $ 6,031.2 $ 6,521.9 $ 2,406.5 $ 20,653.0 Cost Balance at January 1, 2020 $ 5,693.4 $ 15,855.0 $ 33,024.0 $ 8,302.9 $ 62,875.3 Additions — 6,308.9 3,275.8 2,974.8 12,559.5 Disposals or retirements — — (60.5 ) — (60.5 ) Effect of exchange rate changes (256.8 ) (2.2 ) (0.3 ) (0.1 ) (259.4 ) Balance at December 31, 2020 $ 5,436.6 $ 22,161.7 $ 36,239.0 $ 11,277.6 $ 75,114.9 Accumulated amortization and impairment Balance at January 1, 2020 $ — $ 9,823.8 $ 26,502.1 $ 5,896.4 $ 42,222.3 Additions — 2,404.5 3,669.2 1,112.5 7,186.2 Disposals or retirements — — (59.9 ) — (59.9 ) Effect of exchange rate changes — (2.1 ) 0.3 — (1.8 ) Balance at December 31, 2020 $ — $ 12,226.2 $ 30,111.7 $ 7,008.9 $ 49,346.8 Carrying amounts at December 31, 2020 $ 5,436.6 $ 9,935.5 $ 6,127.3 $ 4,268.7 $ 25,768.1

Loans and Bonds Payable (Tables

Loans and Bonds Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Short-term loans [member]
Statement [LineItems]
Summary of Loans and Bonds Payable	December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Unsecured loans Amount $ 118,522.3 $ 88,559.0 Loan content US$ (in millions) $ 2,370.0 $ 200.0 EUR (in millions) 1,410.0 2,398.0 Annual i 0.01%-2.22 % (0.54)%-0.33 % Maturity date Due by May 2020 Due by February
Bonds payable [member]
Statement [LineItems]
Summary of Loans and Bonds Payable	December 31, December 31, 2020 NT$ NT$ (In Millions) (In Millions) Domestic unsecured bonds $ 56,900.0 $ 173,197.0 Overseas unsecured bonds — 84,291.0 Less: Discounts on bonds payable — (782.9 ) Less: Current portion (31,800.0 ) (2,600.0 ) $ 25,100.0 $ 254,105.1
Bonds payable [member] | Taiwan [member]
Statement [LineItems]
Summary of Loans and Bonds Payable	The major terms of domestic unsecured bonds are as follows: Issuance Tranche Issuance Period Total Amount Coupon Repayment and NT$ unsecured bonds 100-2 B January 2012 to January 2019 $ 7,000.0 1.46 % Bullet repayment; interest payable annually 101-1 B August 2012 to August 2019 9,000.0 1.40 % The same as above Issuance Tranche Issuance Period Total Amount Coupon Repayment and 101-2 B September 2012 to September 2019 $ 9,000.0 1.39 % Bullet repayment; interest payable annually 101-3 — October 2012 to October 2022 4,400.0 1.53 % The same as above 101-4 B January 2013 to January 2020 10,000.0 1.35 % The same as above C January 2013 to January 2023 3,000.0 1.49 % The same as above 102-1 B February 2013 to February 2020 11,600.0 1.38 % The same as above C February 2013 to February 2023 3,600.0 1.50 % The same as above 102-2 A July 2013 to July 2020 10,200.0 1.50 % The same as above B July 2013 to July 2023 3,500.0 1.70 % The same as above 102-3 B August 2013 to August 2019 8,500.0 1.52 % The same as above 102-4 C September 2013 to March 2019 1,400.0 1.60 % Bullet repayment; interest payable annually (interest for the six months prior to maturity will accrue on the basis of actual days and be repayable at maturity) D September 2013 to March 2021 2,600.0 1.85 % The same as above E September 2013 to March 2023 5,400.0 2.05 % The same as above F September 2013 to September 2023 2,600.0 2.10 % Bullet repayment; interest payable annually 109-1 A March 2020 to March 2025 3,000.0 0.58 % The same as above B March 2020 to March 2027 10,500.0 0.62 % The same as above C March 2020 to March 2030 10,500.0 0.64 % The same as above 109-2 A April 2020 to April 2025 5,900.0 0.52 % The same as above B April 2020 to April 2027 10,400.0 0.58 % The same as above C April 2020 to April 2030 5,300.0 0.60 % The same as above 109-3 A May 2020 to May 2025 4,500.0 0.55 % The same as above B May 2020 to May 2027 7,500.0 0.60 % The same as above Issuance Tranche Issuance Period Total Amount Coupon Repayment and 109-3 C May 2020 to May 2030 $ 2,400.0 0.64 % Bullet repayment; interest payable annually 109-4 A July 2020 to July 2025 5,700.0 0.58 % Two equal installments in last two years; interest payable annually B July 2020 to July 2027 6,300.0 0.65 % The same as above C July 2020 to July 2030 1,900.0 0.67 % The same as above 109-5 A September 2020 to September 2025 4,800.0 0.50 % The same as above B September 2020 to September 2027 8,000.0 0.58 % The same as above C September 2020 to September 2030 2,800.0 0.60 % The same as above 109-6 (green bond) A December 2020 to December 2025 1,600.0 0.40 % The same as above B December 2020 to December 2027 5,600.0 0.44 % The same as above C December 2020 to December 2030 4,800.0 0.48 % The same as above 109-7 A December 2020 to December 2025 1,900.0 0.36 % The same as above B December 2020 to December 2027 10,200.0 0.41 % The same as above C December 2020 to December 2030 6,400.0 0.45 % The same as above (Concluded) Issuance Tranche Issuance Period Total Amount Coupon Repayment and Interest Payment US$ unsecured bonds 109-1 — September 2020 to September 2060 US$ 1,000.0 2.70 % Bullet repayment (callable on the 5th anniversary of the issue date and every anniversary thereafter); interest payable annually
Bonds payable [member] | Overseas [member]
Statement [LineItems]
Summary of Loans and Bonds Payable	The major terms of overseas unsecured bonds are as follows: Issuance Period Total Amount (In Millions) Coupon Repayment and Interest Payment September 2020 to September 2025 US$ 1,000.0 0.75% Bullet repayment (callable at any time, in whole or in part, at the relevant redemption price according to relevant agreements); interest payable semi-annually September 2020 to September 2027 750.0 1.00% The same as above September 2020 to September 2030 1,250.0 1.375% The same as above
Long-term bank loans [member]
Statement [LineItems]
Summary of Loans and Bonds Payable	December 31, 2020 NT$ (In Millions) Unsecured loans $ 2,000.0 Less: Discounts on government grants (32.4 ) $ 1,967.6 Loan content Annual interest rate 0.4% Maturity date Due by September

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Amounts Recognized in Consolidated Statements of Profit or Loss and Other Comprehensive Income of Defined Benefit Plans	Amounts recognized in respect of these defined benefit plans were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Current service cost $ 137.7 $ 135.6 $ 123.3 Net interest expense 144.1 124.0 81.6 Components of defined benefit costs recognized in profit or loss 281.8 259.6 204.9 Remeasurement on the net defined benefit liability: Return on plan assets (excluding amounts included in net interest expense) (71.3 ) (124.4 ) (139.2 ) Actuarial loss (gain) arising from experience adjustments 334.7 (438.0 ) 494.1 Actuarial gain arising from changes in demographic assumptions — (233.2 ) — Actuarial loss arising from changes in financial assumptions 597.8 541.7 3,161.9 Components of defined benefit costs recognized in other comprehensive income 861.2 (253.9 ) 3,516.8 Total $ 1,143.0 $ 5.7 $ 3,721.7
Pension Costs of Defined Benefit Plans Recognized in Profit or Loss by Categories	The pension costs of the aforementioned defined benefit plans were recognized in profit or loss by the following categories: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Cost of revenue $ 177.8 $ 157.8 $ 126.3 Research and development expenses 79.1 72.7 57.3 General and administrative expenses 20.6 25.1 18.2 Marketing expenses 4.3 4.0 3.1 $ 281.8 $ 259.6 $ 204.9
Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets	The amounts arising from the defined benefit obligation of the Company were as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Present value of defined benefit obligation $ 13,484.1 $ 16,980.3 Fair value of plan assets (4,301.6 ) (5,066.2 ) Net defined benefit liability $ 9,182.5 $ 11,914.1
Fair Value of Plan Assets by Major Categories	The fair value of the plan assets by major categories at the end of reporting period was as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Cash $ 713.2 $ 632.8 Equity instruments 2,313.8 2,926.7 Debt instruments 1,274.6 1,506.7 $ 4,301.6 $ 5,066.2
Principal Assumptions for Actuarial Valuation of Present Value of Defined Benefit Obligation	The actuarial valuations of the present value of the defined benefit obligation were carried out by qualified actuaries. The principal assumptions of the actuarial valuation were as follows: Measurement Date December 31, 2019 December 31, 2020 Discount rate 0.90% 0.40% Future salary increase rate 3.00% 3.00% (Note) Note: The Company has an additional 20 percent pay raise in 2021.
Present value of defined benefit obligation [member]
Statement [LineItems]
Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets	Movements in the present value of the defined benefit obligation were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 12,774.6 $ 13,662.7 $ 13,484.1 Current service cost 137.7 135.6 123.3 Interest expense 207.8 175.4 118.8 Remeasurement: Actuarial loss (gain) arising from experience adjustments 334.7 (438.0 ) 494.1 Actuarial gain arising from changes in demographic assumptions — (233.2 ) — Actuarial loss arising from changes in financial assumptions 597.8 541.7 3,161.9 Benefits paid from plan assets (274.3 ) (344.1 ) (399.0 ) Benefits paid directly by the Company (115.6 ) (16.0 ) (2.9 ) Balance, end of year $ 13,662.7 $ 13,484.1 $ 16,980.3
Fair value of plan assets [member]
Statement [LineItems]
Funded Status of Defined Benefit Plans, Movements in Present Value of Defined Benefit Obligation and Fair Value of Plan Assets	Movements in the fair value of the plan assets were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 3,923.9 $ 4,011.3 $ 4,301.6 Interest income 63.7 51.4 37.2 Remeasurement: Return on plan assets (excluding amounts included in net interest expense) 71.3 124.4 139.2 Contributions from employer 226.7 458.6 987.2 Benefits paid from plan assets (274.3 ) (344.1 ) (399.0 ) Balance, end of year $ 4,011.3 $ 4,301.6 $ 5,066.2

Guarantee Deposits (Tables)

Guarantee Deposits (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Guarantee Deposits	December 31, December 31, NT$ NT$ (In Millions) (In Millions) Capacity guarantee $ 1,499.4 $ — Others 230.5 350.0 $ 1,729.9 $ 350.0 Current portion (classified under accrued expenses and other current liabilities) $ 1,553.0 $ 84.4 Noncurrent portion 176.9 265.6 $ 1,729.9 $ 350.0

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Appropriations of Earnings and Dividends Per Share	The appropriation of 2018 earnings has been approved by TSMC’s shareholders in its meeting held on June 5, 2019. The appropriation and cash dividends per share were as follows: Appropriation of Earnings Cash Dividends Per Share NT$ (NT$) (In Millions) Legal capital reserve $ 35,113.1 Special capital reserve $ (11,459.5 ) Cash dividends to shareholders $ 207,443.0 $ 8.0 The appropriations of 2019 and 2020 quarterly earnings have been approved by TSMC’s Board of Directors in its meeting, respectively. The appropriations and cash dividends per share were as follows: First Quarter Second Quarter Third Quarter Fourth Quarter NT$ NT$ NT$ NT$ Resolution date of TSMC’s Board of Directors in its meeting June 5, 2019 August 13, 2019 November 12, February 11, Special capital reserve $ (4,724.0 ) $ (3,338.2 ) $ 3,289.2 $ 16,893.0 Cash dividends to shareholders $ 51,860.8 $ 64,826.0 $ 64,826.0 $ 64,826.0 Cash dividends per share (NT$) $ 2.0 $ 2.5 $ 2.5 $ 2.5 First Quarter Second Quarter Third Quarter Fourth Quarter NT$ NT$ NT$ NT$ Resolution date of TSMC’s Board of Directors in its meeting May 12, 2020 August 11, 2020 November 10, February Special capital reserve $ (2,694.8 ) $ 11,884.5 $ 5,501.3 $ 12,420.7 Cash dividends to shareholders $ 64,826.0 $ 64,826.0 $ 64,826.0 $ 64,826.0 Cash dividends per share (NT$) $ 2.5 $ 2.5 $ 2.5 $ 2.5
Changes in Other Reserves	Changes in others were as follows: Year Ended December 31, 2018 Foreign Unrealized Gain (Loss) on Unearned Total NT$ (In Millions) NT$ NT$ NT$ NT$ Balance, beginning of year(IFRS 9) $ (26,697.7 ) $ (524.9 ) $ 4.2 $ (10.3 ) $ (27,228.7 ) Exchange differences arising on translation of foreign operations 14,562.0 — — — 14,562.0 Year Ended December 31, 2018 Foreign Unrealized Gain (Loss) on Unearned Total NT$ (In Millions) NT$ NT$ NT$ NT$ Unrealized gain (loss) on financial assets at FVTOCI Equity instruments $ — $ (3,311.6 ) $ — $ — $ (3,311.6 ) Debt instruments — (1,858.0 ) — — (1,858.0 ) Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — 1,193.1 — — 1,193.1 Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — 989.1 — — 989.1 Loss allowance adjustments from debt instruments — (2.0 ) — — (2.0 ) Gain (loss) arising on changes in the fair value of hedging instruments — — 41.0 — 41.0 Transferred to initial carrying amount of hedged items — — (22.2 ) — (22.2 ) Share of other comprehensive income (loss) of associates 93.3 (6.8 ) — — 86.5 Share of unearned stock-based employee compensation of associates — — — 8.5 8.5 Income tax effect — 91.8 0.6 — 92.4 Balance, end of year $ (12,042.4 ) $ (3,429.3 ) $ 23.6 $ (1.8 ) $ (15,449.9 ) Year Ended December 31, 2019 Foreign Unrealized Gain (Loss) on Unearned Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Balance, beginning of year $ (12,042.4 ) $ (3,429.3 ) $ 23.6 $ (1.8 ) $ (15,449.9 ) Exchange differences arising on translation of foreign operations (14,693.5 ) — — — (14,693.5 ) Unrealized gain (loss) on financial assets at FVTOCI Equity instruments — 334.5 — — 334.5 Debt instruments — 3,097.3 — — 3,097.3 Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — (162.1 ) — — (162.1 ) Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — (537.8 ) — — (537.8 ) Loss allowance adjustments from debt instruments — 6.9 — — 6.9 Gain (loss) arising on changes in the fair value of hedging instruments — — (109.6 ) — (109.6 ) Other comprehensive income transferred to profit or loss due to disposal of subsidiary 4.6 — — — 4.6 Transferred to initial carrying amount of hedged items — — 82.3 — 82.3 Share of other comprehensive income (loss) of associates (140.1 ) (11.8 ) (0.1 ) — (152.0 ) Share of unearned stock-based employee compensation of associates — — — 1.6 1.6 Income tax effect — 9.4 — — 9.4 Balance, end of year $ (26,871.4 ) $ (692.9 ) $ (3.8 ) $ (0.2 ) $ (27,568.3 ) Year Ended December 31, 2020 Foreign Unrealized Gain (Loss) on Unearned Total NT$ NT$ NT$ NT$ NT$ Balance, beginning of year $ (26,871.4 ) $ (692.9 ) $ (3.8 ) $ (0.2 ) $ (27,568.3 ) Exchange differences arising on translation of foreign operations (29,846.8 ) — — — (29,846.8 ) Unrealized gain (loss) on financial assets at FVTOCI Equity instruments — 423.2 — — 423.2 Debt instruments — 3,907.0 — — 3,907.0 Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal — 108.7 — — 108.7 Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal — (1,439.4 ) — — (1,439.4 ) Loss allowance adjustments from debt instruments — (0.9 ) — — (0.9 ) Gain (loss) arising on changes in the fair value of hedging instruments — — 24.1 — 24.1 Transferred to initial carrying amount of hedged items — — (20.3 ) — (20.3 ) Share of other comprehensive income (loss) of associates (283.4 ) 15.5 — — (267.9 ) Share of unearned stock-based employee compensation of associates — — — 0.2 0.2 Income tax effect — 0.6 — — 0.6 Balance, end of year $ (57,001.6 ) $ 2,321.8 $ — $ — $ (54,679.8 )
Capital Stock - Common Stock [member]
Statement [LineItems]
Summary of Capital Stock and Capital Surplus	a. Capital stock December 31, December 31, NT$ NT$ (In Millions) (In Millions) Authorized shares 28,050.0 28,050.0 Authorized capital $ 280,500.0 $ 280,500.0 Issued and paid shares 25,930.3 25,930.3 Issued capital $ 259,303.8 $ 259,303.8
Capital Surplus [member]
Statement [LineItems]
Summary of Capital Stock and Capital Surplus	b. Capital surplus December 31, December 31, NT$ NT$ (In Millions) (In Millions) Additional paid-in $ 24,185.0 $ 24,185.0 From merger 22,804.5 22,804.5 From convertible bonds 8,892.9 8,892.9 From share of changes in equities of subsidiaries 121.8 121.8 From share of changes in equities of associates 302.2 302.5 Donations 33.3 40.5 $ 56,339.7 $ 56,347.2

Net Revenue (Tables)

Net Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Disaggregation of Revenue from Contracts with Customers	a. Disaggregation of revenue from contracts with customers Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Product (In Millions) (In Millions) (In Millions) Wafer $ 911,296.4 $ 927,317.3 $ 1,178,456.3 Others 120,177.2 142,668.1 160,798.5 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Geography (In Millions) (In Millions) (In Millions) Taiwan $ 78,260.8 $ 84,255.2 $ 129,082.9 United States 632,821.5 634,713.0 817,911.0 China 175,794.2 208,101.4 233,783.3 Europe, the Middle East and Africa 71,068.5 67,568.2 70,213.4 Japan 58,125.9 57,468.6 63,299.2 Others 15,402.7 17,879.0 24,965.0 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 The Company categorized the net revenue mainly based on the countries where the customers are headquartered. Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Platform (In Millions) (In Millions) (In Millions) Smartphone $ 466,452.3 $ 523,612.9 $ 645,303.6 High Performance Computing 341,910.2 315,822.3 439,810.0 Internet of Things 65,091.3 86,342.7 110,355.2 Automotive 51,709.8 47,914.5 44,367.5 Digital Consumer Electronics 58,470.2 53,733.4 54,555.7 Others 47,839.8 42,559.6 44,862.8 $ 1,031,473.6 $ 1,069,985.4 $ 1,339,254.8 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ Resolution (In Millions) (In Millions) (In Millions) 5-nanometer $ — $ — $ 90,934.5 7-nanometer 81,680.7 249,548.1 394,837.0 10-nanometer 96,989.5 23,266.4 3,403.1 16-nanometer 187,370.6 186,700.9 197,959.0 20-nanometer 23,618.4 9,535.8 8,450.9 28-nanometer 178,440.4 149,578.7 149,367.7 40/45-nanometer 101,801.0 93,366.3 103,176.5 65-nanometer 76,122.3 69,250.0 61,226.7 90-nanometer 36,652.1 25,624.2 29,380.4 0.11/0.13 micron 20,677.7 22,947.3 33,197.1 0.15/0.18 micron 81,182.6 77,564.5 86,008.5 0.25 micron and above 26,761.1 19,935.1 20,514.9 Wafer revenue $ 911,296.4 $ 927,317.3 $ 1,178,456.3
Summary of Contract Balances	b. Contract balances January 1, 2019 December 31, 2019 December 31, 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Contract liabilities (classified under accrued expenses and other current liabilities) $ 4,684.0 $ 6,784.3 $ 13,775.1

Interest Income (Tables)

Interest Income (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of interest income	Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Interest income Bank deposit s $ 10,310.7 $ 11,454.0 $ 5,139.1 Financial assets at FVTPL 382.7 339.5 2.5 Financial assets at FVTOCI 3,078.6 3,476.2 3,121.9 Financial assets at amortized cost 922.4 919.7 754.9 $ 14,694.4 $ 16,189.4 $ 9,018.4

Finance Costs (Tables)

Finance Costs (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Finance Costs	Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Interest expense Corporate bo n $ 1,633.8 $ 1,139.9 $ 1,337.3 Bank loans 1,417.3 1,869.4 500.9 Lease liabilities — 240.9 227.8 Others 0.1 0.7 15.5 $ 3,051.2 $ 3,250.9 $ 2,081.5

Other Gains and Losses, Net (Ta

Other Gains and Losses, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Other Gains and Losses	Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Gain (loss) on disposal of financial assets, net Investments in debt instruments at FVTOCI $ (989.1 ) $ 537.8 $ 1,439.4 Loss on disposal of subsidiaries — (4.6 ) — Gain (loss) on financial instruments at FVTPL, net Mandatorily measured at FVT P (2,293.9 ) (2,360.7 ) 8,244.5 Gain (loss) arising from fair value hedges, net (2.3 ) 13.1 — The reversal (accrual) of expected credit loss of financial assets Investments in debt instruments at FVTOCI 2.0 (6.9 ) 0.9 Financial assets at amortized cost 0.4 5.2 (4.6 ) Other gains (losses), net (127.9 ) 665.1 426.2 $ (3,410.8 ) $ (1,151.0 ) $ 10,106.4

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Income Tax Expense	Income tax expense consisted of the following: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Current income tax expense Current tax expense recognized in the current year $ 60,584.3 $ 47,135.5 $ 87,452.7 Income tax adjustments on prior years (21,753.0 ) (10,193.8 ) (7,589.4 ) Other income tax adjustments 152.9 (41.5 ) 150.2 38,984.2 36,900.2 80,013.5 Deferred income tax benefit Effect of tax rate changes (1,474.8 ) — — The origination and reversal of temporary differences (3,072.5 ) (1,065.1 ) (6,275.2 ) (4,547.3 ) (1,065.1 ) (6,275.2 ) Income tax expense recognized in profit or loss $ 34,436.9 $ 35,835.1 $ 73,738.3
Reconciliation of Income before Income Tax and Income Tax Expense Recognized in Profit or Loss	A reconciliation of inc o Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Income before tax $ 397,543.1 $ 389,862.1 $ 584,746.3 Income tax expense at the statutory rate $ 80,872.5 $ 79,056.5 $ 118,831.3 Tax effect of adjusting items: Nondeductible (deductible) items in determining taxable income 2,533.4 (4,183.5 ) 1,015.9 Tax-exempt (54,543.5 ) (39,808.1 ) (65,988.1 ) Additional income tax under the Alternative Minimum Tax Act 21,455.9 10,367.9 18,872.8 Additional income tax on unappropriated earnings 16,294.5 7,628.1 14,747.3 Effect of tax rate changes on deferred income tax (1,474.8 ) — — The origination and reversal of temporary differences (3,072.6 ) (1,065.1 ) (6,275.2 ) Income tax credits (6,028.4 ) (5,925.4 ) (26.5 ) 56,037.0 46,070.4 81,177.5 Income tax adjustments on prior years (21,753.0 ) (10,193.8 ) (7,589.4 ) Other income tax adjustments 152.9 (41.5 ) 150.2 Income tax expense recognized in profit or loss $ 34,436.9 $ 35,835.1 $ 73,738.3
Income Tax Expense Recognized in Other Comprehensive Income	b. Income tax expense recognized in other comprehensive income Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Deferred income tax benefit (expense) Related to remeasurement of defined benefit obligation $ 103.3 $ (30.4 ) $ 422.1 Related to unrealized gain/loss on investments in equity instruments at FVTOCI 91.8 9.4 0.6 Related to gain/loss on cash flow hedges 0.6 — — $ 195.7 $ (21.0 ) $ 422.7
Analysis of Deferred Income Tax Assets and Liabilities in Consolidated Statements of Financial Position	The analysis of deferred income tax assets and liabilities was as follows: December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 13,547.2 $ 19,354.4 Refund liability 2,150.4 3,755.1 Net defined benefit liability 1,016.3 1,342.1 Unrealized loss on inventories 469.4 858.5 Deferred compensation cost 323.1 330.3 Investments in equity instruments at FVTOCI 65.7 66.3 Others 356.3 251.5 $ 17,928.4 $ 25,958.2 Deferred income tax liabilities Temporary differences Unrealized exchange gains (333.6 ) (866.5 ) Others (10.8 ) (863.4 ) $ (344.4 ) $ (1,729.9 ) Year Ended December 31, 2018 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 8,401.3 $ 3,430.4 $ — $ 7.5 $ 11,839.2 Refund liability 1,637.7 955.0 — 1.3 2,594.0 Net defined benefit liability 975.3 6.3 103.3 — 1,084.9 Unrealized loss on inventories 629.5 120.5 — 1.0 751.0 Deferred compensation cost 266.5 (4.7 ) — 9.9 271.7 Investments in equity instruments at FVTOCI — — 56.2 — 56.2 Others 195.2 7.1 — 7.1 209.4 $ 12,105.5 $ 4,514.6 $ 159.5 $ 26.8 $ 16,806.4 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (169.5 ) $ 107.8 $ — $ — $ (61.7 ) Investments in equity instruments at FVTOCI (95.4 ) — 95.4 — — Others (37.3 ) (75.1 ) (59.2 ) — (171.6 ) $ (302.2 ) $ 32.7 $ 36.2 $ — $ (233.3 ) Year Ended December 31, 2019 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 11,839.2 $ 1,727.8 $ — $ (19.8 ) $ 13,547.2 Refund liability 2,594.0 (443.2 ) — (0.4 ) 2,150.4 Net defined benefit liability 1,084.9 (38.2 ) (30.4 ) — 1,016.3 Unrealized loss on inventories 751.0 (280.8 ) — (0.8 ) 469.4 Deferred compensation cost 271.7 59.4 — (8.0 ) 323.1 Investments in equity instruments at FVTOCI 56.2 0.1 9.4 — 65.7 Others 209.4 151.1 — (4.2 ) 356.3 $ 16,806.4 $ 1,176.2 $ (21.0 ) $ (33.2 ) $ 17,928.4 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (61.7 ) $ (271.9 ) $ — $ — $ (333.6 ) Others (171.6 ) 160.8 — — (10.8 ) $ (233.3 ) $ (111.1 ) $ — $ — $ (344.4 ) Year Ended December 31, 2020 Recognized in Balance, Profit or Loss Other Effect of Balance, End of Year NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Deferred income tax assets Temporary differences Depreciation $ 13,547.2 $ 5,824.0 $ — $ (16.8 ) $ 19,354.4 Refund liability 2,150.4 1,606.1 — (1.4 ) 3,755.1 Net defined benefit liability 1,016.3 (96.3 ) 422.1 — 1,342.1 Unrealized loss on inventories 469.4 391.1 — (2.0 ) 858.5 Deferred compensation cost 323.1 27.4 — (20.2 ) 330.3 Investments in equity instruments at FVTOCI 65.7 — 0.6 — 66.3 Others 356.3 (91.6 ) — (13.2 ) 251.5 $ 17,928.4 $ 7,660.7 $ 422.7 $ (53.6 ) $ 25,958.2 Deferred income tax liabilities Temporary differences Unrealized exchange gains $ (333.6 ) $ (532.9 ) $ — $ — $ (866.5 ) Others (10.8 ) (852.6 ) — — (863.4 ) $ (344.4 ) $ (1,385.5 ) $ — $ — $ (1,729.9 )
Tax-exemption Information Related to Profits Generated from Certain Projects	As of December 31, 2020, the profits generated from the following projects of TSMC are exempt from income tax for a five-year period: Tax-exemption Period Construction and expansion of 2009 by TSMC 2018 to 2022

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Computation of Earnings Per Share	Years Ended December 31 2018 2019 2020 (NT$) (NT$) (NT$) Basic EPS $ 14.00 $ 13.65 $ 19.70 Diluted EPS $ 14.00 $ 13.65 $ 19.70 EPS is computed as follows: Amounts NT$ (In Millions) Number of EPS (NT$) Year Ended December 31, 2018 Basic/Diluted EPS Net income available to common shareholders of the parent $ 363,052.7 25,930.3 $ 14.00 Year Ended December 31, 2019 Basic/Diluted EPS Net income available to common shareholders of the parent $ 353,948.0 25,930.3 $ 13.65 Amounts NT$ (In Millions) Number of EPS (NT$) Year Ended December 31, 2020 Basic/Diluted EPS Net income available to common shareholders of the parent $ 510,744.0 25,930.3 $ 19.70

Additional Information of Exp_2

Additional Information of Expenses by Nature (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Additional Information of Expenses by Nature	Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) a.   Depreciation of property, plant and equipment and right-of-use Recognized in cost of revenue $ 264,804.7 $ 256,530.9 $ 299,311.4 Recognized in operating expenses 23,292.3 24,856.7 25,191.3 Recognized in other operating income and expenses 27.9 24.2 35.7 $ 288,124.9 $ 281,411.8 $ 324,538.4 b.  Amortization of intangible assets Recognized in cost of revenue $ 2,073.5 $ 3,069.9 $ 4,837.7 Recognized in operating expenses 2,347.9 2,402.5 2,348.5 $ 4,421.4 $ 5,472.4 $ 7,186.2 c.   Employee benefits expenses Post-employment benefits Defined contribution plans $ 2,568.9 $ 2,609.7 $ 2,809.5 Defined benefit plans 281.8 259.6 204.9 2,850.7 2,869.3 3,014.4 Other employee benefits 105,364.2 107,115.3 137,803.0 $ 108,214.9 $ 109,984.6 $ 140,817.4 Employee benefits expense summarized by function Recognized in cost of revenue $ 63,597.7 $ 64,702.0 $ 83,099.0 Recognized in operating expenses 44,617.2 45,282.6 57,718.4 $ 108,214.9 $ 109,984.6 $ 140,817.4
Summary of Accrued Profit Sharing Bonus to Employees	Accrued profit sharing bonus to employees is illustrated below:
Summary of Profit Sharing Bonus to Employees and Compensation to Directors

Summary Of Profit Sharing Bonus

Summary Of Profit Sharing Bonus To Employees And Compensation to Directors (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Disclosure Of Detailed Information About Profit Sharing Bonus To Employees And Directors Compensation	TSMC’s profit sharing bonus to employees and compensation to directors for 2018, 2019 and 2020 had been approved by the Board of Directors of TSMC, as illustrated below: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Resolution Date of TSMC’s Board of Directors in its meeting February 19, 2019 February 11, 2020 February 9, 2021 Profit sharing bonus to employees $ 23,570.0 $ 23,165.7 $ 34,753.2 Compensation to directors $ 349.3 $ 360.4 $ 509.8

Cash Flow Information (Tables)

Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Schedule of Detailed Information about Non Cash Transaction	31. CASH FLOW INFORMATION a.   Non-cash Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Additions of financial assets at FVTOCI $ 100,759.6 $ 257,824.5 $ 268,653.5 Conversion of convertible bonds into equity securities (23.8 ) — (120.5 ) Changes in accrued expenses and other current liabilities (4,323.0 ) (266.3 ) (5,895.5 ) Payments for acquisition of financial assets at FVTOCI $ 96,412.8 $ 257,558.2 $ 262,637.5 Disposal of financial assets at FVTOCI $ 90,545.1 $ 229,525.1 $ 269,011.8 Changes in other financial assets (3,905.8 ) 919.4 (2,079.9 ) Proceeds from disposal of financial assets at FVTOCI $ 86,639.3 $ 230,444.5 $ 266,931.9 Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Additions of property, plant and equipment $ 300,024.4 $ 564,283.0 $ 525,720.7 Changes in other financial assets 1,555.4 472.5 584.7 Exchange of assets — (3,287.1 ) (1.1 ) Changes in payables to contractors and equipment suppliers 13,979.9 (100,963.9 ) (19,085.9 ) Transferred to initial carrying amount of hedged items 22.2 (82.3 ) 20.3 Payments for acquisition of property, plant and equipment $ 315,581.9 $ 460,422.2 $ 507,238.7 Additions of intangible assets $ 7,105.0 $ 9,237.7 $ 12,559.5 Changes in other financial assets 22.8 22.2 10.5 Changes in account payable (27.5 ) 70.0 191.4 Changes in accrued expenses and other current liabilities — — (3,219.0 ) Payments for acquisition of intangible assets $ 7,100.3 $ 9,329.9 $ 9,542.4 (Concluded)
Schedule of Liabilities Arising From Financing Activities	b. Reconciliation of liabilities arising from financing activities Non-cash changes Balance as of January 1, 2018 Financing Cash Flow Foreign Exchange Movement Other Changes (Note) Balance as of December 31, 2019 NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 63,766.8 $ 23,923.0 $ 1,064.9 $ — $ 88,754.7 Bonds payable 150,201.1 (58,024.9 ) (382.9 ) 6.7 91,800.0 Guarantee deposits 16,080.6 (279.2 ) 423.5 (6,035.9 ) 10,189.0 Total $ 230,048.5 $ (34,381.1 ) $ 1,105.5 $ (6,029.2 ) $ 190,743.7 Non-cash changes Balance as of Financing Cash Flow Foreign Exchange Movement Leases Modifications Other Changes (Note) Balance as of December 31, 2019 NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 88,754.7 $ 31,804.3 $ (2,036.7 ) $ — $ — $ 118,522.3 Bonds payable 91,800.0 (34,900.0 ) — — — 56,900.0 Lease liabilities 19,903.6 (3,174.0 ) (73.3 ) 419.7 240.9 17,316.9 Guarantee deposits 10,189.0 (639.1 ) 4.5 — (7,824.5 ) 1,729.9 Total $ 210,647.3 $ (6,908.8 ) $ (2,105.5 ) $ 419.7 $ (7,583.6 ) $ 194,469.1 Non-cash changes Balance as of Financing Cash Flow Foreign Exchange Movement Leases Modifications Other Changes (Note) Balance as of December 31, 2020 NT$ NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) Short-term loans $ 118,522.3 $ (31,571.6 ) $ 1,608.3 $ — $ — $ 88,559.0 Bonds payable 56,900.0 204,535.0 (4,758.6 ) — 28.7 256,705.1 Long-term bank loans — 2,000.0 — — (32.4 ) 1,967.6 Lease liabilities 17,316.9 (2,819.7 ) (78.5 ) 7,742.2 227.7 22,388.6 Guarantee deposits 1,729.9 129.5 1.8 — (1,511.2 ) 350.0 Total $ 194,469.1 $ 172,273.2 $ (3,227.0 ) $ 7,742.2 $ (1,287.2 ) $ 369,970.3 Note: Other changes include amortization of bonds payable, amortization of long-term bank loan interest subsidy, financial cost of lease liabilities and guarantee deposits refunded to customers by offsetting related accounts receivable.

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Statement [LineItems]
Categories of Financial Instruments	a. Categories of financial instruments December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Financial assets FVTPL (Note 1) $ 326.8 $ 2,259.4 FVTOCI (Note 2) 134,776.8 129,918.7 Hedging financial assets 25.9 0.1 Amortized cost (Note 3) 612,740.6 826,293.6 $ 747,870.1 $ 958,471.8 Financial liabilities FVTPL (Note 4) $ 982.3 $ 94.1 Hedging financial liabilities 1.8 1.2 Amortized cost (Note 5) 533,581.7 748,129.3 $ 534,565.8 $ 748,224.6 Note 1: Financial assets mandatorily measured at FVTPL. Note 2: Including notes and accounts receivable (net), equity and debt investments. Note 3: Including cash and cash equivalents, financial assets at amortized cost, notes and accounts receivable (including related parties), other receivables and refundable deposits. Note 4: Held for trading. Note 5: Including short-term loans, accounts payable (including related parties), payables to contractors and equipment suppliers, cash dividends payable, accrued expenses and other current liabilities, bonds payable, long-term bank loans and guarantee deposits.
Summary of Current Credit Risk Assessment Policies	The Company assesses the 12-month Category Description Basis for Recognizing Expected Credit Loss Expected Performing Credit rating is investment grade on valuation date 12 months expected credit loss 0—0.1% Doubtful Credit rating is non-investment Lifetime expected credit loss-not — In default Credit rating is CC or below on valuation date Lifetime expected credit loss-credit impaired — Write-off There is evidence indicating that the debtor is in severe financial difficulty and the Company has no realistic prospect of recovery Amount is written off —
Summary of Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments, Including Principal and Interest	The table below summarizes the maturity profile of the Company’s financial liabilities based on contractual undiscounted payments, including principal and interest. Less Than 1 Year 1-3 Years 3-5 Years More Than 5 Years Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) December 31, 2019 Non-derivative Short-term loans $ 118,562.6 $ — $ — $ — $ 118,562.6 Accounts payable (including related parties) 40,206.0 — — — 40,206.0 Payables to contractors and equipment suppliers 140,810.7 — — — 140,810.7 Accrued expenses and other current liabilities 45,760.9 — — — 45,760.9 Bonds payable 32,338.9 7,777.7 18,203.6 — 58,320.2 Lease liabilities (including those classified under accrued expenses and other current liabilities) 2,475.1 2,782.9 2,484.5 10,947.7 18,690.2 Guarantee deposits (including those classified under accrued expenses and other current liabilities) 1,553.0 121.0 55.5 0.4 1,729.9 381,707.2 10,681.6 20,743.6 10,948.1 424,080.5 Derivative financial instruments Forward exchange contracts Outflows 141,450.8 — — — 141,450.8 Inflows (141,128.9 ) — — — (141,128.9 ) 321.9 — — — 321.9 $ 382,029.1 $ 10,681.6 $ 20,743.6 $ 10,948.1 $ 424,402.4 December 31, 2020 Non-derivative Short-term loans $ 88,557.5 $ — $ — $ — $ 88,557.5 Accounts payable (including related parties) 41,095.0 — — — 41,095.0 Payables to contractors and equipment suppliers 157,805.0 — — — 157,805.0 Accrued expenses and other current liabilities 71,995.7 — — — 71,995.7 Bonds payable 5,328.0 27,631.6 59,986.8 207,152.1 300,098.5 Long-term bank loans 8.0 847.4 1,170.9 — 2,026.3 Lease liabilities (including those classified under accrued expenses and other current liabilities) 2,024.2 3,566.7 3,198.8 15,067.9 23,857.6 Guarantee deposits (including those classified under accrued expenses and other current liabilities) 84.4 113.5 151.8 0.3 350.0 366,897.8 32,159.2 64,508.3 222,220.3 685,785.6 Derivative financial instruments Forward exchange contracts Outflows 177,764.2 — — — 177,764.2 Inflows (181,458.0 ) — — — (181,458.0 ) (3,693.8 ) — — — (3,693.8 ) $ 363,204.0 $ 32,159.2 $ 64,508.3 $ 222,220.3 $ 682,091.8
Summary of Additional Information About In Maturity Lease Liabilities	Information about the maturity analysis for lease liabilities more than 5 years: 5-10 10-15 15-20 More Than 20 Years Total NT$ NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) (In Millions) December 31, 2019 Lease liabilities $ 5,581.1 $ 3,691.3 $ 1,600.9 $ 74.4 $ 10,947.7 December 31, 2020 Lease liabilities $ 7,402.0 $ 5,253.9 $ 2,255.2 $ 156.8 $ 15,067.9
Summary of Level 3 Fair Value Were Financial Assets at FVTPL and Equity Investments classified as Financial Assets at FVTOCI	The financial assets measured at Level 3 fair value were financial assets at FVTPL and equity investments classified as financial assets at FVTOCI. Reconciliations for the years ended December 31, 2018, 2019 and 2020 were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Balance, beginning of year $ 5,841.4 $ 3,910.7 $ 4,208.9 Additions 212.5 372.3 175.2 Recognized in profit or loss — — (3.8 ) Recognized in other comprehensive income (2,141.4 ) 129.5 409.0 Disposals and proceeds from return of capital of investments (175.8 ) (76.5 ) (51.1 ) Transfers out of level 3 (Note) — (43.6 ) — Effect of exchange rate changes 174.0 (83.5 ) (223.3 ) Balance, end of year $ 3,910.7 $ 4,208.9 $ 4,514.9
Measured at fair value on a recurring basis [member]
Statement [LineItems]
Fair Value of Financial Instruments	The following table presents the Company’s financial assets and liabilities measured at fair value on a recurring basis: December 31, 2019 Level 1 Level 2 Level 3 Total NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) Financial assets at FVTPL Mandatorily measured at FVTPL Forward exchange contracts $ — $ 162.1 $ — $ 162.1 Convertible bonds — — 123.8 123.8 Agency mortgage-backed securities — 40.9 — 40.9 $ — $ 203.0 $ 123.8 $ 326.8 Financial assets at FVTOCI Investments in debt instruments Agency bonds/Agency mortgage-backed securities $ — $ 51,966.5 $ — $ 51,966.5 Corporate bonds — 51,790.0 — 51,790.0 Government bonds 12,678.1 146.1 — 12,824.2 Asset-backed securities — 10,815.9 — 10,815.9 Investments in equity instruments Non-publicly — 39.2 4,085.1 4,124.3 Notes and accounts receivable, net — 3,255.9 — 3,255.9 $ 12,678.1 $ 118,013.6 $ 4,085.1 $ 134,776.8 Hedging financial assets Fair value hedges Interest rate futures contracts $ 22.4 $ — $ — $ 22.4 Cash flow hedges Forward exchange contracts — 3.5 — 3.5 $ 22.4 $ 3.5 $ — $ 25.9 Financial liabilities at FVTPL Held for trading Forward exchange contracts $ — $ 982.3 $ — $ 982.3 Hedging financial liabilities Cash flow hedges Forward exchange contracts $ — $ 1.8 $ — $ 1.8 December 31, 2020 Level 1 Level 2 Level 3 Total NT$ NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) (In Millions) Financial assets at FVTPL Mandatorily measured at FVTPL Forward exchange contracts $ — $ 2,259.4 $ — $ 2,259.4 Financial assets at FVTOCI Investments in debt instruments Corporate bonds $ — $ 56,593.6 $ — $ 56,593.6 Agency bonds/Agency mortgage-backed securities — 43,977.1 — 43,977.1 Government bonds 13,279.2 180.3 — 13,459.5 Asset-backed securities — 8,368.3 — 8,368.3 Investments in equity instruments Non-publicly — — 4,514.9 4,514.9 Publicly traded stocks 50.0 — — 50.0 Notes and accounts receivable, net — 2,955.3 — 2,955.3 $ 13,329.2 $ 112,074.6 $ 4,514.9 $ 129,918.7 Hedging financial assets Fair value hedges Interest rate futures contracts $ 0.1 $ — $ — $ 0.1 Financial liabilities at FVTPL Held for trading Forward exchange contracts $ — $ 94.1 $ — $ 94.1 Hedging financial liabilities Fair value hedges Interest rate futures contracts $ 1.2 $ — $ — $ 1.2
Not measured at fair value but for which the fair value is disclosed [member]
Statement [LineItems]
Fair Value of Financial Instruments	The table below sets out the fair value hierarchy for the Company’s financial assets and liabilities which are not required to measure at fair value: December 31, 2019 Carrying Level 2 Amount Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets Financial assets at amortized costs Corporate bonds $ 7,648.8 $ 7,718.7 Financial liabilities Financial liabilities at amortized costs Bonds payable $ 56,900.0 $ 57,739.1 December 31, 2020 Carrying Level 2 Amount Fair Value NT$ NT$ (In Millions) (In Millions) Financial assets Financial assets at amortized costs Corporate bonds $ 10,970.2 $ 11,053.6 Financial liabilities Financial liabilities at amortized costs Bonds payable $ 256,705.1 $ 257,551.2

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Summary of Significant Transactions between the Company and Other Related Parties	b. Net revenue Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Item Related Party Categories Net revenue from sale of goods Associates $ 8,980.1 $ 6,253.9 $ 8,129.8 Other related parties 0.3 — — $ 8,980.4 $ 6,253.9 $ 8,129.8 Net revenue from royalties Associates $ 362.3 $ 183.6 $ 195.1 c. Purchases Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Related Party Categories Associates $ 8,809.5 $ 6,301.4 $ 7,606.4 d. Receivables from related parties December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Item Related Party Name/Categories Receivables from related parties GUC $ 741.9 $ 370.6 Xintec 120.2 187.5 $ 862.1 $ 558.1 Other receivables from related parties SSMC $ 46.5 $ 45.3 VIS 3.9 4.3 Other associates 1.2 1.0 $ 51.6 $ 50.6 e. Payables to related parties December 31, 2019 December 31, 2020 NT$ NT$ (In Millions) (In Millions) Item Related Party Name/Categories Payables to related parties Xintec $ 736.9 $ 1,358.6 SSMC 487.9 400.8 VIS 154.0 311.4 Other associates 56.1 36.9 $ 1,434.9 $ 2,107.7 f. Others Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Item Related Party Categories Manufacturing expenses Associates $ 2,974.6 $ 2,823.0 $ 5,440.0 Research and development expenses Associates $ 83.1 $ 163.4 $ 256.5 General and administrative expenses Other related parties $ 120.8 $ 120.0 $ 120.0
Compensation to Directors and Other Key Management Personnel	The compensation to directors and other key management personnel were as follows: Years Ended December 31 2018 2019 2020 NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Short-term employee benefits $ 2,004.9 $ 1,922.2 $ 2,666.7 Post-employment benefits 3.4 2.7 2.3 $ 2,008.3 $ 1,924.9 $ 2,669.0

Operating Segments Information

Operating Segments Information (Tables)	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Geographic Information	1) Geographic information December 31, December 31, 2019 2020 NT$ NT$ Noncurrent Assets (In Millions) (In Millions) Taiwan $ 1,344,352.6 $ 1,569,080.4 United States 8,850.1 9,455.5 China 38,586.6 34,456.4 Europe, the Middle East and Africa 186.2 174.2 Japan 27.1 327.2 Others 3.1 3.0 $ 1,392,005.7 $ 1,613,496.7
Major Customers Representing at Least 10% of Net Revenue	2) Major custom e Years Ended December 31 2018 2019 2020 Amount % Amount % Amount % NT$ NT$ NT$ (In Millions) (In Millions) (In Millions) Customer A $ 224,690.7 22 $ 247,213.3 23 $ 336,775.5 25 Customer B 83,885.6 8 152,876.9 14 167,390.8 12

U.S. Dollar Amounts - Additiona

U.S. Dollar Amounts - Additional Information (Detail)	Dec. 31, 2020
Disclosure of basis of preparation of financial statements [abstract]
Reporting currency for translation, exchange rate	28.08

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Detail Information of Subsidiaries (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
TSMC North America [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Selling and marketing of integrated circuits and other semiconductor devices	Selling and marketing of integrated circuits and other semiconductor devices
Establishment and Operating Location	San Jose, California, U.S.A.	San Jose, California, U.S.A.
Percentage of Ownership	100.00%	100.00%
TSMC Europe B.V. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Customer service and supporting activities	Customer service and supporting activities
Establishment and Operating Location	Amsterdam, the Netherlands	Amsterdam, the Netherlands
Percentage of Ownership	100.00%	100.00%
TSMC Japan Limited [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Customer service and supporting activities	Customer service and supporting activities
Establishment and Operating Location	Yokohama, Japan	Yokohama, Japan
Percentage of Ownership	100.00%	100.00%
TSMC Design Technology Japan, Inc. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Engineering support activities	Engineering support activities
Establishment and Operating Location	Yokohama, Japan	Yokohama, Japan
Percentage of Ownership	100.00%
TSMC Korea Limited [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Customer service and supporting activities	Customer service and supporting activities
Establishment and Operating Location	Seoul, Korea	Seoul, Korea
Percentage of Ownership	100.00%	100.00%
TSMC Partners, Ltd. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in companies involved in the design, manufacture, and other related business in the semiconductor industry and other investment activities	Investing in companies involved in the design, manufacture, and other related business in the semiconductor industry and other investment activities
Establishment and Operating Location	Tortola, British Virgin Islands	Tortola, British Virgin Islands
Percentage of Ownership	100.00%	100.00%
TSMC Global, Ltd. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investment activities	Investment activities
Establishment and Operating Location	Tortola, British Virgin Islands	Tortola, British Virgin Islands
Percentage of Ownership	100.00%	100.00%
TSMC China Company Limited [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices	Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices
Establishment and Operating Location	Shanghai, China	Shanghai, China
Percentage of Ownership	100.00%	100.00%
TSMC Nanjing Company Limited [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices	Manufacturing, selling, testing and computer-aided design of integrated circuits and other semiconductor devices
Establishment and Operating Location	Nanjing, China	Nanjing, China
Percentage of Ownership	100.00%	100.00%
VisEra Technologies Company Ltd. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Engaged in manufacturing electronic spare parts and in researching, developing, designing, manufacturing, selling, packaging and testing of color filter	Engaged in manufacturing electronic spare parts and in researching, developing, designing, manufacturing, selling, packaging and testing of color filter
Establishment and Operating Location	Hsin-Chu, Taiwan	Hsin-Chu, Taiwan
Percentage of Ownership	87.00%	87.00%
TSMC Arizona Corporation [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Manufacturing, selling and testing of integrated circuits and other semiconductor devices
Establishment and Operating Location	Phoenix, Arizona, U.S.A.
Percentage of Ownership	100.00%
VentureTech Alliance Fund II, L.P. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in new start-up technology companies	Investing in new start-up technology companies
Establishment and Operating Location	Cayman Islands	Cayman Islands
Percentage of Ownership	98.00%	98.00%
VentureTech Alliance Fund III, L.P. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in new start-up technology companies	Investing in new start-up technology companies
Establishment and Operating Location	Cayman Islands	Cayman Islands
Percentage of Ownership	98.00%	98.00%
TSMC Development, Inc. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in companies involved in the manufacturing related business in the semiconductor industry	Investing in companies involved in the manufacturing related business in the semiconductor industry
Establishment and Operating Location	Delaware, U.S.A.	Delaware, U.S.A.
Percentage of Ownership	100.00%	100.00%
TSMC Technology, Inc. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Engineering support activities	Engineering support activities
Establishment and Operating Location	Delaware, U.S.A.	Delaware, U.S.A.
Percentage of Ownership	100.00%	100.00%
TSMC Design Technology Canada Inc. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Engineering support activities	Engineering support activities
Establishment and Operating Location	Ontario, Canada	Ontario, Canada
Percentage of Ownership	100.00%	100.00%
InveStar Semiconductor Development Fund, Inc. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in new start-up technology companies	Investing in new start-up technology companies
Establishment and Operating Location	Cayman Islands	Cayman Islands
Percentage of Ownership		97.00%
InveStar Semiconductor Development Fund, Inc. (II) LDC. [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in new start-up technology companies	Investing in new start-up technology companies
Establishment and Operating Location	Cayman Islands	Cayman Islands
Percentage of Ownership		97.00%
WaferTech, LLC [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Manufacturing, selling and testing of integrated circuits and other semiconductor devices	Manufacturing, selling and testing of integrated circuits and other semiconductor devices
Establishment and Operating Location	Washington, U.S.A.	Washington, U.S.A.
Percentage of Ownership	100.00%	100.00%
Growth Fund Limited [member]
Disclosure of subsidiaries [line items]
Main Businesses and Products	Investing in new start-up technology companies	Investing in new start-up technology companies
Establishment and Operating Location	Cayman Islands	Cayman Islands
Percentage of Ownership	100.00%	100.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Detail Information of Subsidiaries (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
TSMC Nanjing Company Limited [member]
Disclosure of subsidiaries [line items]
Investment in subsidiaries		$ 3,000
TSMC Arizona Corporation [member]
Disclosure of subsidiaries [line items]
Conditioned payments for various public infrastructure projects from City of Phoenix	$ 205

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020
Land improvements [member]
Disclosure of significant accounting policies [line items]
Useful lives of property, plant and equipment	20 years
Buildings (assets used by the Company and assets subject to operating leases) [member] | Bottom of range [member]
Disclosure of significant accounting policies [line items]
Useful lives of property, plant and equipment	10 years
Buildings (assets used by the Company and assets subject to operating leases) [member] | Top of range [member]
Disclosure of significant accounting policies [line items]
Useful lives of property, plant and equipment	20 years
Machinery and equipment [member]
Disclosure of significant accounting policies [line items]
Useful lives of property, plant and equipment	5 years
Office equipment [member]
Disclosure of significant accounting policies [line items]
Useful lives of property, plant and equipment	5 years

Cash and Cash Equivalents - Sum

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018TWD ($)	Dec. 31, 2017TWD ($)
Disclosure of financial assets [abstract]
Cash and deposits in banks	$ 653,580.6		$ 452,734.4
Government bonds	3,716.1		2,188.1
Repurchase agreements	1,750.4
Commercial paper	1,123.5		476.8
Cash and cash equivalents	$ 660,170.6	$ 23,510.4	$ 455,399.3	$ 16,217.9	$ 577,814.6	$ 553,391.7

Financial Assets and Liabilit_3

Financial Assets and Liabilities at Fair Value through Profit or Loss - Summary of Financial Assets and Liabilities at Fair Value through Profit or Loss (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Financial assets, Mandatorily measured at FVTPL	$ 2,259.4	$ 326.8
Forward exchange contracts [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, Held for trading	94.1	982.3
Financial assets, Mandatorily measured at FVTPL	$ 2,259.4	162.1
Convertible Bonds [Member]
Disclosure of detailed information about financial instruments [line items]
Financial assets, Mandatorily measured at FVTPL		123.8
Agency bonds/Agency mortgage-backed securities [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets, Mandatorily measured at FVTPL		$ 40.9

Financial Assets and Liabilit_4

Financial Assets and Liabilities at Fair Value through Profit or Loss - Outstanding Forward Exchange Contracts for which Hedge Accounting Treatment is not Applied (Detail) ¥ in Millions, $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2019JPY (¥)
Sell NT$ | Bottom of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date	2021-01	2020-01
Sell NT$ | Top of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date	2021-03	2020-06
Sell NT$ | Sell [member]
Disclosure of detailed information about financial instruments [line items]
Contract Amount	$ 144,698	$ 108,428
Sell JPY | Bottom of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date		2020-01
Sell JPY | Top of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date		2020-02
Sell JPY | Sell [member]
Disclosure of detailed information about financial instruments [line items]
Contract Amount | ¥					¥ 57,471.6
Sell US$ | Bottom of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date	2021-01	2020-01
Sell US$ | Top of range [member]
Disclosure of detailed information about financial instruments [line items]
Maturity Date	2021-03	2020-03
Sell US$ | Sell [member]
Disclosure of detailed information about financial instruments [line items]
Contract Amount			$ 1,176.9	$ 529.2

Financial Assets at Fair Valu_3

Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Financial Assets at Fair Value through Other Comprehensive Income (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Disclosure of financial assets [line items]
Current	$ 122,448.5		$ 127,396.6
Non current	4,514.9	$ 160.8	4,124.3
Investment in equity and debt instruments at FVTOCI	126,963.4		131,520.9
Debt securities [member]
Disclosure of financial assets [line items]
Investments in debt instruments at FVTOCI	122,398.5		127,396.6
Debt securities [member] | Corporate bonds [member]
Disclosure of financial assets [line items]
Investments in debt instruments at FVTOCI	56,593.6		51,790
Debt securities [member] | Agency bonds/Agency mortgage-backed securities [member]
Disclosure of financial assets [line items]
Investments in debt instruments at FVTOCI	43,977.1		51,966.5
Debt securities [member] | Government bonds [member]
Disclosure of financial assets [line items]
Investments in debt instruments at FVTOCI	13,459.5		12,824.2
Debt securities [member] | Asset-backed securities [Member]
Disclosure of financial assets [line items]
Investments in debt instruments at FVTOCI	8,368.3		10,815.9
Equity instruments [member]
Disclosure of financial assets [line items]
Investment in equity instruments at FVTOCI	4,564.9		4,124.3
Equity instruments [member] | Non-publicly traded stocks [member]
Disclosure of financial assets [line items]
Investment in equity instruments at FVTOCI	4,514.9		$ 4,124.3
Equity instruments [member] | Publicly traded stocks [member]
Disclosure of financial assets [line items]
Investment in equity instruments at FVTOCI	$ 50

Financial Assets at Fair Valu_4

Financial Assets at Fair Value Through Other Comprehensive Income - Additional Information (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial assets at fair value through other comprehensive income [abstract]
Proceeds from sale of shares	$ 10	$ 873,500	$ 840,600
Unrealized gain (loss) on investments in equity instruments at fair value through other comprehensive income	109,000	156,800	$ 1,193,100
Cumulative loss allowance for expected credit loss	$ 32,500	$ 35,600

Financial Assets at Amortized_3

Financial Assets at Amortized Cost - Schedule of Financial Assets at Amortized Cost (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of financial assets [line items]
Less: Allowance for impairment loss	$ (246.6)		$ (325.3)	$ (7.3)
Corporate bonds	10,970.2		7,648.8
Current portion	6,598	$ 235	299.9
Noncurrent portion	4,372.2	$ 155.7	7,348.9
Corporate bonds [member]
Disclosure of financial assets [line items]
Less: Allowance for impairment loss	(7.1)		(2.9)
Corporate bonds	$ 10,977.3		$ 7,651.7

Hedging Financial Instruments -

Hedging Financial Instruments - Summary of hedging financial instruments (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial assets- current
Financial assets current	$ 0.1	$ 25.9
Financial liabilities- current
Financial liabilities current	1.2	1.8
Fair value hedges [member] | Interest rate futures contracts [member]
Financial assets- current
Financial assets current	0.1	22.4
Financial liabilities- current
Financial liabilities current	$ 1.2
Cash flow hedges [member] | Forward exchange contracts [member]
Financial assets- current
Financial assets current		3.5
Financial liabilities- current
Financial liabilities current		$ 1.8

Hedging Financial Instruments_2

Hedging Financial Instruments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020
Cash flow hedges [member]
Disclosure of detailed information about financial instruments [line items]
Description of forward exchange contracts maturity	maturities of 12 months or less.
Interest rate futures contracts [member]
Disclosure of detailed information about financial instruments [line items]
Hedge ratio adjustment percentage	100.00%
Forward exchange contracts and foreign currency deposits [member] | Cash flow hedges [member]
Disclosure of detailed information about financial instruments [line items]
Hedge ratio adjustment percentage	100.00%

Hedging Financial Instruments_3

Hedging Financial Instruments - Summary of Information Related to Hedges of Interest Rate Risk (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	$ 24.1	$ 0.9	$ (109.6)	$ 41
Fair value hedges [member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness			$ 13.1	(2.3)
US treasury bonds interest rate futures contracts [member]
Disclosure of detailed information about financial instruments [line items]
Contract Amount					$ 88.7	$ 122.2
Maturity	March 2021	March 2021	March 2020
US treasury bonds interest rate futures contracts [member] | Fair value hedges [member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	$ (353.6)		$ (164.7)	11.5
FVTOCI [member]
Disclosure of detailed information about financial instruments [line items]
Asset Carrying Amount	6,198.7		7,364.7
Asset Accumulated Amount of Fair Value Hedge Adjustments	1.1		(22.4)
FVTOCI [member] | Fair value hedges [member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	$ 353.6		$ 177.8	$ (13.8)

Hedging Financial Instruments_4

Hedging Financial Instruments - Summary of Information Relating to Hedges for Foreign Currency Risk (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	$ 24.1	$ 0.9	$ (109.6)	$ 41
Cash flow hedges [member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	24.1		(109.6)	41
Cash flow hedges [member] | Forecast Transaction Capital Expenditures [member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	(24.1)		109.6	(41)
Cash flow hedges [member] | Forward exchange contracts [member]
Disclosure of detailed information about financial instruments [line items]
Contract Amount			$ 1,342.4
Maturity			January 2020
Balance in Other Equity (Continuing Hedges)			$ (3.8)
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness	$ 24.1		$ (109.6)	34.6
Cash flow hedges [member] | Foreign currency deposits [Member]
Disclosure of detailed information about financial instruments [line items]
Increase (Decrease) in Value Used for Calculating Hedge Ineffectiveness				$ 6.4

Notes and Accounts Receivable_3

Notes and Accounts Receivable, Net - Summary of Notes and Accounts Receivable, Net (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of information about of trade accounts and notes receivables [line items]
Less: Loss allowance	$ (246.6)		$ (325.3)	$ (7.3)
Notes and accounts receivable	145,480.3	$ 5,180.9	138,908.6
Trade receivables [member]
Disclosure of information about of trade accounts and notes receivables [line items]
Notes and accounts receivable	142,525		135,652.7
Trade receivables [member] | Amortized cost [member]
Disclosure of information about of trade accounts and notes receivables [line items]
Less: Loss allowance	(246.6)		(325.3)
Notes and accounts receivable	142,771.6		135,978
Trade receivables [member] | FVTOCI [member]
Disclosure of information about of trade accounts and notes receivables [line items]
Notes and accounts receivable	$ 2,955.3		$ 3,255.9

Notes and Accounts Receivable_4

Notes and Accounts Receivable, Net - Aging Analysis of Notes and Accounts Receivable, Net (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of financial assets [line items]
Notes and accounts receivable, net	$ 145,480.3	$ 5,180.9	$ 138,908.6
Less: Loss allowance	(246.6)		(325.3)	$ (7.3)
Allowance for credit losses [member]
Disclosure of financial assets [line items]
Less: Loss allowance	(246.6)		(325.3)
Not past due [member]
Disclosure of financial assets [line items]
Notes and accounts receivable, net	140,933.6		126,134.8
Past due [member] | Past due within 30 days [member]
Disclosure of financial assets [line items]
Notes and accounts receivable, net	4,784.4		13,082.1
Past due [member] | Past due 31-60 days [member]
Disclosure of financial assets [line items]
Notes and accounts receivable, net	8.7		12.8
Past due [member] | Past due 61-120 days [member]
Disclosure of financial assets [line items]
Notes and accounts receivable, net	0.1		1
Past due [member] | Past due over 121 days [member]
Disclosure of financial assets [line items]
Notes and accounts receivable, net	$ 0.1		$ 3.2

Notes and Accounts Receivable_5

Notes and Accounts Receivable, Net - Movements of Allowance for Doubtful Receivables (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of financial assets [line items]
Beginning balance	$ 325.3	$ 7.3
Reversal/Write-off	(78.5)	318.2
Effect of exchange rate changes	(0.2)	(0.2)
Ending balance	$ 246.6	325.3	$ 7.3
IFRS 9 [member]
Disclosure of financial assets [line items]
Beginning balance		$ 7.3	227
Reversal/Write-off			(219.7)
Ending balance			$ 7.3

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Classes of current inventories [abstract]
Finished goods	$ 21,705.6		$ 8,924.5
Work in process	91,672.9		51,969.1
Raw materials	14,716		16,552.3
Supplies and spare parts	9,258.9		5,535.3
Inventories, total	$ 137,353.4	$ 4,891.5	$ 82,981.2

Inventories - Summary of Write

Inventories - Summary of Write downs reversals of Inventories (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Write-downs (reversals of write-downs) of inventories [abstract]
Write downs Reversals of Inventories	$ 3,664.5	$ (1,983)	$ 1,259.5

Investments Accounted for Usi_3

Investments Accounted for Using Equity Method - Summary of Investments in Associates (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2020USD ($)
Disclosure of associates [line items]
Carrying Amount	$ 18,730.2	$ 18,618.8	$ 667
Vanguard International Semiconductor Corporation [member]
Disclosure of associates [line items]
Principal Activities	Manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing and design service of masks	Manufacturing, selling, packaging, testing and computer-aided design of integrated circuits and other semiconductor devices and the manufacturing and design service of masks
Place of Incorporation and Operation	Hsinchu, Taiwan	Hsinchu, Taiwan
Carrying Amount	$ 8,964.1	$ 8,960.5
% of Ownership and Voting Rights Held by the Company	28.00%	28.00%
Systems on Silicon Manufacturing Company Pte Ltd. [member]
Disclosure of associates [line items]
Principal Activities	Manufacturing and selling of integrated circuits and other semiconductor devices	Manufacturing and selling of integrated circuits and other semiconductor devices
Place of Incorporation and Operation	Singapore	Singapore
Carrying Amount	$ 5,900.2	$ 6,502.2
% of Ownership and Voting Rights Held by the Company	39.00%	39.00%
Xintec Inc. [member]
Disclosure of associates [line items]
Principal Activities	Wafer level chip size packaging and wafer level post passivation interconnection service	Wafer level chip size packaging and wafer level post passivation interconnection service
Place of Incorporation and Operation	Taoyuan, Taiwan	Taoyuan, Taiwan
Carrying Amount	$ 2,522.3	$ 1,842.8
% of Ownership and Voting Rights Held by the Company	41.00%	41.00%
Global Unichip Corporation [member]
Disclosure of associates [line items]
Principal Activities	Researching, developing, manufacturing, testing and marketing of integrated circuits	Researching, developing, manufacturing, testing and marketing of integrated circuits
Place of Incorporation and Operation	Hsinchu, Taiwan	Hsinchu, Taiwan
Carrying Amount	$ 1,315.4	$ 1,274.8
% of Ownership and Voting Rights Held by the Company	35.00%	35.00%
Mutual-Pak [member]
Disclosure of associates [line items]
Principal Activities	Manufacturing of electronic parts, wholesaling and retailing of electronic materials, and researching, developing and testing of RFID	Manufacturing of electronic parts, wholesaling and retailing of electronic materials, and researching, developing and testing of RFID
Place of Incorporation and Operation	New Taipei, Taiwan	New Taipei, Taiwan
Carrying Amount	$ 28.2	$ 38.5
% of Ownership and Voting Rights Held by the Company	28.00%	28.00%

Investments Accounted for Usi_4

Investments Accounted for Using Equity Method - Market Prices of Investments Accounted for Using Equity Method in Publicly Traded Stocks Calculated by Closing Price at End of Reporting Period (Detail) - Level 1 [member] - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Vanguard International Semiconductor Corporation [member]
Disclosure of associates [line items]
Closing Price in Active Markets	$ 53,849.9	$ 36,812.9
Xintec Inc. [member]
Disclosure of associates [line items]
Closing Price in Active Markets	20,420.2	8,958.2
Global Unichip Corporation [member]
Disclosure of associates [line items]
Closing Price in Active Markets	$ 15,827.2	$ 11,251.8

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Property, Plant and Equipment-2018 (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	$ 1,352,377.4		$ 1,072,050.3
Additions (Deductions)	525,720.7		564,283	$ 300,024.4
Ending balance	$ 1,555,589.1	$ 55,398.5	1,352,377.4	1,072,050.3
Land and Land Improvements [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			3,460.8
Ending balance				3,460.8
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			200,340.2
Ending balance				200,340.2
Machinery and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			679,481.2
Impairment				423.5
Ending balance				679,481.2
Office equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			15,857.1
Ending balance				15,857.1
Equipment under installation and construction in progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			172,911
Ending balance				172,911
Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			3,372,779.1	3,080,615.1
Additions (Deductions)				300,024.4
Disposals or retirements				(7,174.2)
Effect of exchange rate changes				(686.2)
Ending balance				3,372,779.1
Cost [member] | Land and Land Improvements [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			4,011.4	3,983.2
Effect of exchange rate changes				28.2
Ending balance				4,011.4
Cost [member] | Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			418,714.3	379,134.6
Additions (Deductions)				40,396.4
Disposals or retirements				(410.9)
Effect of exchange rate changes				(405.8)
Ending balance				418,714.3
Cost [member] | Machinery and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,728,760.2	2,487,752.3
Additions (Deductions)				247,042.3
Disposals or retirements				(5,972.5)
Effect of exchange rate changes				(61.9)
Ending balance				2,728,760.2
Cost [member] | Office equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			48,382.2	42,391.5
Additions (Deductions)				6,773.4
Disposals or retirements				(790.8)
Effect of exchange rate changes				8.1
Ending balance				48,382.2
Cost [member] | Equipment under installation and construction in progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			172,911	167,353.5
Additions (Deductions)				5,812.3
Effect of exchange rate changes				(254.8)
Ending balance				172,911
Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,300,728.8	2,018,072.8
Additions (Deductions)				288,124.9
Disposals or retirements				(5,962.6)
Impairment				423.5
Effect of exchange rate changes				70.2
Ending balance				2,300,728.8
Accumulated depreciation [member] | Land and Land Improvements [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			550.6	510.5
Additions (Deductions)				20.9
Effect of exchange rate changes				19.2
Ending balance				550.6
Accumulated depreciation [member] | Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			218,374.1	194,446.5
Additions (Deductions)				24,293.4
Disposals or retirements				(399)
Effect of exchange rate changes				33.2
Ending balance				218,374.1
Accumulated depreciation [member] | Machinery and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,049,279	1,795,448.9
Additions (Deductions)				258,195.3
Disposals or retirements				(4,773.6)
Impairment				423.5
Effect of exchange rate changes				(15.1)
Ending balance				2,049,279
Accumulated depreciation [member] | Office equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			$ 32,525.1	27,666.9
Additions (Deductions)				5,615.3
Disposals or retirements				(790)
Effect of exchange rate changes				32.9
Ending balance				$ 32,525.1

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Operating lease term	1 year	1 year
Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Operating lease term	5 years	5 years
Main plants [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives for property, plant and equipment	20 years	20 years	20 years
Mechanical and electrical power equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives for property, plant and equipment	10 years	10 years	10 years
Clean rooms [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives for property, plant and equipment	10 years	10 years	10 years
Machinery and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Reversal of impairment		$ 301.4
Impairment loss recognized			$ 423.5

Property, Plant and Equipment_3

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure Of The Ownership Details Of PropertyPlant And Equipment [Line Items]
Property, plant and equipment	$ 1,555,589.1	$ 55,398.5	$ 1,352,377.4	$ 1,072,050.3
Asset used by the Company [member]
Disclosure Of The Ownership Details Of PropertyPlant And Equipment [Line Items]
Property, plant and equipment	1,554,585.9		1,352,313.9
Asset subject to operating lease [member]
Disclosure Of The Ownership Details Of PropertyPlant And Equipment [Line Items]
Property, plant and equipment	$ 1,003.2		$ 63.5

Property, Plant and Equipment_4

Property, Plant and Equipment - Summary of assets used by the Company (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	$ 1,352,377.4		$ 1,072,050.3
Additions	525,720.7		564,283	$ 300,024.4
Ending balance	1,555,589.1	$ 55,398.5	1,352,377.4	1,072,050.3
Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	1,352,313.9
Ending balance	1,554,585.9		1,352,313.9
Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			3,372,779.1	3,080,615.1
Additions				300,024.4
Disposals or retirements				(7,174.2)
Effect of exchange rate changes				(686.2)
Ending balance				3,372,779.1
Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,911,596.3		3,372,216.5
Additions	525,720.7		564,283
Disposals or retirements	(7,172.9)		(18,583.9)
Transfers from assets subject to operating leases	23.1
Transfers to assets subject to operating leases	(1,199)
Transfers from right-of-use assets			619.8
Effect of disposal of subsidiary			(0.5)
Effect of exchange rate changes	(2,744.4)		(6,938.6)
Ending balance	4,426,223.8		3,911,596.3	3,372,216.5
Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,300,728.8	2,018,072.8
Additions				288,124.9
Disposals or retirements				(5,962.6)
Impairment				423.5
Effect of exchange rate changes				70.2
Ending balance				2,300,728.8
Accumulated depreciation [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	2,559,282.4		2,300,253.9
Additions	321,821.1		278,764.9
Disposals or retirements	(6,773.2)		(14,067.3)
Reversal of impairment			(301.4)
Transfers from assets subject to operating leases	8.2
Transfers to assets subject to operating leases	(202.6)
Transfers from right-of-use assets			20.7
Effect of disposal of subsidiary			(0.5)
Impairment	10.2
Effect of exchange rate changes	(2,508.2)		(5,387.9)
Ending balance	2,871,637.9		2,559,282.4	2,300,253.9
Land and Land Improvements [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			3,460.8
Ending balance				3,460.8
Land and Land Improvements [Member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,453.1
Ending balance	3,436.5		3,453.1
Land and Land Improvements [Member] | Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			4,011.4	3,983.2
Effect of exchange rate changes				28.2
Ending balance				4,011.4
Land and Land Improvements [Member] | Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,991.8		4,011.4
Effect of exchange rate changes	(49.2)		(19.6)
Ending balance	3,942.6		3,991.8	4,011.4
Land and Land Improvements [Member] | Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			550.6	510.5
Additions				20.9
Effect of exchange rate changes				19.2
Ending balance				550.6
Land and Land Improvements [Member] | Accumulated depreciation [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	538.7		550.6
Additions	1.5		1.6
Effect of exchange rate changes	(34.1)		(13.5)
Ending balance	506.1		538.7	550.6
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			200,340.2
Ending balance				200,340.2
Buildings [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	195,015.7
Ending balance	250,647.9		195,015.7
Buildings [member] | Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			418,714.3	379,134.6
Additions				40,396.4
Disposals or retirements				(410.9)
Effect of exchange rate changes				(405.8)
Ending balance				418,714.3
Buildings [member] | Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	438,075		418,151.7
Additions	84,882.5		21,448.5
Disposals or retirements	(41.5)		(159)
Transfers from assets subject to operating leases	23.1
Effect of exchange rate changes	(491.7)		(1,366.2)
Ending balance	522,447.4		438,075	418,151.7
Buildings [member] | Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			218,374.1	194,446.5
Additions				24,293.4
Disposals or retirements				(399)
Effect of exchange rate changes				33.2
Ending balance				218,374.1
Buildings [member] | Accumulated depreciation [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	243,059.3		217,899.2
Additions	29,209.1		26,026.6
Disposals or retirements	(27.9)		(144.4)
Transfers from assets subject to operating leases	8.2
Effect of exchange rate changes	(449.2)		(722.1)
Ending balance	271,799.5		243,059.3	217,899.2
Machinery and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			679,481.2
Reversal of impairment			(301.4)
Impairment				423.5
Ending balance				679,481.2
Machinery and equipment | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	608,357
Ending balance	1,051,475.7		608,357
Machinery and equipment | Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,728,760.2	2,487,752.3
Additions				247,042.3
Disposals or retirements				(5,972.5)
Effect of exchange rate changes				(61.9)
Ending balance				2,728,760.2
Machinery and equipment | Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	2,886,623		2,728,760.2
Additions	729,943.3		179,798.4
Disposals or retirements	(6,397.3)		(17,381.6)
Transfers to assets subject to operating leases	(1,199)
Transfers from right-of-use assets			619.8
Effect of exchange rate changes	(1,964.3)		(5,173.8)
Ending balance	3,607,005.7		2,886,623	2,728,760.2
Machinery and equipment | Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			2,049,279	1,795,448.9
Additions				258,195.3
Disposals or retirements				(4,773.6)
Impairment				423.5
Effect of exchange rate changes				(15.1)
Ending balance				2,049,279
Machinery and equipment | Accumulated depreciation [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	2,278,266		2,049,279
Additions	285,393.6		246,724.2
Disposals or retirements	(6,012.9)		(12,880.8)
Reversal of impairment			(301.4)
Transfers to assets subject to operating leases	(202.6)
Transfers from right-of-use assets			20.7
Impairment	10.2
Effect of exchange rate changes	(1,924.3)		(4,575.7)
Ending balance	2,555,530		2,278,266	2,049,279
Office equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			15,857.1
Ending balance				15,857.1
Office equipment [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	17,193
Ending balance	25,060.4		17,193
Office equipment [member] | Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			48,382.2	42,391.5
Additions				6,773.4
Disposals or retirements				(790.8)
Effect of exchange rate changes				8.1
Ending balance				48,382.2
Office equipment [member] | Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	54,611.4		48,382.2
Additions	15,112.9		7,415
Disposals or retirements	(734.1)		(1,043.3)
Effect of disposal of subsidiary			(0.5)
Effect of exchange rate changes	(127.5)		(142)
Ending balance	68,862.7		54,611.4	48,382.2
Office equipment [member] | Accumulated depreciation [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			32,525.1	27,666.9
Additions				5,615.3
Disposals or retirements				(790)
Effect of exchange rate changes				32.9
Ending balance				32,525.1
Office equipment [member] | Accumulated depreciation [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	37,418.4		32,525.1
Additions	7,216.9		6,012.5
Disposals or retirements	(732.4)		(1,042.1)
Effect of disposal of subsidiary			(0.5)
Effect of exchange rate changes	(100.6)		(76.6)
Ending balance	43,802.3		37,418.4	32,525.1
Equipment under installation and construction in progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			172,911
Ending balance				172,911
Equipment under installation and construction in progress [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	528,295.1
Ending balance	223,965.4		528,295.1
Equipment under installation and construction in progress [member] | Cost [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance			172,911	167,353.5
Additions				5,812.3
Effect of exchange rate changes				(254.8)
Ending balance				172,911
Equipment under installation and construction in progress [member] | Cost [member] | Property, plant and equipment not subject to operating leases [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	528,295.1		172,911
Additions	(304,218)		355,621.1
Effect of exchange rate changes	(111.7)		(237)
Ending balance	$ 223,965.4		$ 528,295.1	$ 172,911

Property, Plant and Equipment_5

Property, Plant and Equipment - Summary of assets subject to operating leases (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	$ 1,352,377.4		$ 1,072,050.3
Additions	525,720.7		564,283	$ 300,024.4
Ending balance	1,555,589.1	$ 55,398.5	1,352,377.4	1,072,050.3
Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	63.5
Ending balance	1,003.2		63.5
Cost [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			3,372,779.1	3,080,615.1
Additions				300,024.4
Disposals or retirements				(7,174.2)
Ending balance				3,372,779.1
Cost [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	562.6		562.6
Transfers to assets subject to operating leases	(23.1)
Transfers from assets subject to operating leases	1,199
Disposals or retirements	(311.9)
Ending balance	1,426.6		562.6	562.6
Accumulated depreciation [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			2,300,728.8	2,018,072.8
Additions				288,124.9
Disposals or retirements				(5,962.6)
Ending balance				2,300,728.8
Accumulated depreciation [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	499.1		474.9
Additions	35.7		24.2
Transfers to assets subject to operating leases	(8.2)
Transfers from assets subject to operating leases	202.6
Disposals or retirements	(305.8)
Ending balance	423.4		499.1	474.9
Buildings [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			200,340.2
Ending balance				200,340.2
Buildings [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	63.5
Ending balance	26.2		63.5
Buildings [member] | Cost [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			418,714.3	379,134.6
Additions				40,396.4
Disposals or retirements				(410.9)
Ending balance				418,714.3
Buildings [member] | Cost [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	562.6		562.6
Transfers to assets subject to operating leases	(23.1)
Disposals or retirements	(311.9)
Ending balance	227.6		562.6	562.6
Buildings [member] | Accumulated depreciation [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			218,374.1	194,446.5
Additions				24,293.4
Disposals or retirements				(399)
Ending balance				218,374.1
Buildings [member] | Accumulated depreciation [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance	499.1		474.9
Additions	16.3		24.2
Transfers to assets subject to operating leases	(8.2)
Disposals or retirements	(305.8)
Ending balance	201.4		499.1	474.9
Machinery and equipment [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			679,481.2
Ending balance				679,481.2
Machinery and equipment [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Ending balance	977
Machinery and equipment [member] | Cost [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			2,728,760.2	2,487,752.3
Additions				247,042.3
Disposals or retirements				(5,972.5)
Ending balance				2,728,760.2
Machinery and equipment [member] | Cost [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Transfers from assets subject to operating leases	1,199
Ending balance	1,199
Machinery and equipment [member] | Accumulated depreciation [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Beginning balance			$ 2,049,279	1,795,448.9
Additions				258,195.3
Disposals or retirements				(4,773.6)
Ending balance				$ 2,049,279
Machinery and equipment [member] | Accumulated depreciation [member] | Buildings used to operating leases [member]
Disclosure Of Property Plant And Equipment Subject To Operating Lease [Line Items]
Additions	19.4
Transfers from assets subject to operating leases	202.6
Ending balance	$ 222

Property, Plant and Equipment_6

Property, Plant and Equipment - Summary of maturity analysis of operating lease payments receivable (Detail) - Operating Lease Agreement [Member] - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Maturity Analysis Of Operating Lease Receivables [Line Items]
Operating Lease Payment Receivables	$ 166.1	$ 52.4
Year 1 [member]
Disclosure Of Maturity Analysis Of Operating Lease Receivables [Line Items]
Operating Lease Payment Receivables	149.1	18.4
Year 2 [Member]
Disclosure Of Maturity Analysis Of Operating Lease Receivables [Line Items]
Operating Lease Payment Receivables	$ 17	17
Year 3 [member]
Disclosure Of Maturity Analysis Of Operating Lease Receivables [Line Items]
Operating Lease Payment Receivables		$ 17

Lease Arrangements - Minimum Le

Lease Arrangements - Minimum Lease Payments Expensed (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018TWD ($)
Disclosure Of Finance Lease And Operating Leases By Lessee [Abstract]
Minimum lease payments	$ 4,243.1

Lease Arrangements - Future Min

Lease Arrangements - Future Minimum Lease Payments under Non-cancellable Operating Leases (Detail) $ in Millions	Dec. 31, 2018TWD ($)
Disclosure of maturity analysis of operating lease payments [line items]
Minimum lease payments	$ 20,849.6
Not later than 1 year [member]
Disclosure of maturity analysis of operating lease payments [line items]
Minimum lease payments	5,824.1
Later than 1 year and not later than 5 years [member]
Disclosure of maturity analysis of operating lease payments [line items]
Minimum lease payments	5,834.9
Later than 5 years [member]
Disclosure of maturity analysis of operating lease payments [line items]
Minimum lease payments	$ 9,190.6

Lease Arrangements - Right-of-u

Lease Arrangements - Right-of-use Assets (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2020USD ($)
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use assets	$ 27,728.5	$ 17,232.4	$ 987.5
Additions to right-of-use assets	13,481.2	1,033
Depreciation of right-of-use assets	2,681.6	2,622.7
Income from subleasing right-of-use assets (classified under other operating income and expenses, net)	79.6	55
Land [member]
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use assets	25,141.9	14,064
Depreciation of right-of-use assets	1,312.9	957.1
Buildings [member]
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use assets	2,544.8	2,351.8
Depreciation of right-of-use assets	569.5	458.8
Machinery and equipment [member]
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use assets		775.8
Depreciation of right-of-use assets	775.8	1,184.4
Office equipment [member]
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use assets	41.8	40.8
Depreciation of right-of-use assets	$ 23.4	$ 22.4

Lease Arrangements - Lease Liab

Lease Arrangements - Lease Liabilities (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Lease liabilities [abstract]
Current portion (classified under accrued expenses and other current liabilities)	$ 1,828		$ 2,275.1
Noncurrent portion	20,560.6	$ 732.2	15,041.8
Lease liabilities	$ 22,388.6		$ 17,316.9

Lease Arrangements - Ranges Of

Lease Arrangements - Ranges Of Discount Rates For Lease Liabilities (Detail)	Dec. 31, 2020	Dec. 31, 2019
Land [member] | Bottom of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	0.48%	0.67%
Land [member] | Top of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	2.14%	2.14%
Buildings [member] | Bottom of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	0.54%	0.67%
Buildings [member] | Top of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	3.88%	3.88%
Machinery [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities		3.24%
Office equipment [member] | Bottom of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	0.28%	0.64%
Office equipment [member] | Top of range [member]
Disclosure Of Discount Rate On Lease Liabilities [Line Items]
Discount rate on lease liabilities	3.88%	3.88%

Lease Arrangements - Maturity A

Lease Arrangements - Maturity Analysis of Lease Payments Receivable Under Operating Subleases (Detail) - Operating Sublease Agreement [Member] - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Maturity Analysis Of Operating Lease Receivables Under Subleases [Line Items]
Maturity analysis of lease payments receivable	$ 144.1	$ 60.5
Year 1 [Member]
Disclosure Of Maturity Analysis Of Operating Lease Receivables Under Subleases [Line Items]
Maturity analysis of lease payments receivable	$ 144.1	58.6
Year 2 [Member]
Disclosure Of Maturity Analysis Of Operating Lease Receivables Under Subleases [Line Items]
Maturity analysis of lease payments receivable		$ 1.9

Lease Arrangements - Other leas

Lease Arrangements - Other lease information (Details) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Presentation of leases for lessee [abstract]
Expenses relating to short-term leases	$ 3,153.5	$ 5,007.1
Expenses relating to low-value asset leases	0.3	0.5
Expenses relating to variable lease payments not included in the measurement of lease liabilities	257	195.1
Total cash outflow for leases	$ 6,354.6	$ 7,724.4

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	$ 20,653		$ 17,002.1
Ending balance	25,768.1	$ 917.7	20,653	$ 17,002.1
Cost [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	62,875.3		54,020.9	46,994.3
Additions	12,559.5		9,237.8	7,105
Disposals or retirements	(60.5)		(260.9)	(217.9)
Effect of exchange rate changes	(259.4)		(122.5)	139.5
Ending balance	75,114.9		62,875.3	54,020.9
Accumulated amortization [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	42,222.3		37,018.8	32,819.1
Additions	7,186.2		5,472.4	4,421.4
Disposals or retirements	(59.9)		(258.6)	(217.8)
Effect of exchange rate changes	(1.8)		(10.3)	(3.9)
Ending balance	49,346.8		42,222.3	37,018.8
Goodwill [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	5,693.4		5,795.5
Ending balance	5,436.6		5,693.4	5,795.5
Goodwill [member] | Cost [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	5,693.4		5,795.5	5,648.7
Effect of exchange rate changes	(256.8)		(102.1)	146.8
Ending balance	5,436.6		5,693.4	5,795.5
Technology license fees [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	6,031.2		2,218.5
Ending balance	9,935.5		6,031.2	2,218.5
Technology license fees [member] | Cost [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	15,855		10,974.5	10,443.3
Additions	6,308.9		4,879.6	533.7
Effect of exchange rate changes	(2.2)		0.9	(2.5)
Ending balance	22,161.7		15,855	10,974.5
Technology license fees [member] | Accumulated amortization [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	9,823.8		8,756	7,694.9
Additions	2,404.5		1,066.9	1,063.6
Effect of exchange rate changes	(2.1)		0.9	(2.5)
Ending balance	12,226.2		9,823.8	8,756
Software and system design costs [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	6,521.9		6,570.9
Ending balance	6,127.3		6,521.9	6,570.9
Software and system design costs [member] | Cost [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	33,024		29,594.6	25,186.3
Additions	3,275.8		3,710.4	4,601.9
Disposals or retirements	(60.5)		(260.9)	(186.7)
Effect of exchange rate changes	(0.3)		(20.1)	(6.9)
Ending balance	36,239		33,024	29,594.6
Software and system design costs [member] | Accumulated amortization [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	26,502.1		23,023.7	20,376.7
Additions	3,669.2		3,747.3	2,835.3
Disposals or retirements	(59.9)		(258.6)	(186.6)
Effect of exchange rate changes	0.3		(10.3)	(1.7)
Ending balance	30,111.7		26,502.1	23,023.7
Patent and others [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	2,406.5		2,417.2
Ending balance	4,268.7		2,406.5	2,417.2
Patent and others [member] | Cost [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	8,302.9		7,656.3	5,716
Additions	2,974.8		647.8	1,969.4
Disposals or retirements				(31.2)
Effect of exchange rate changes	(0.1)		(1.2)	2.1
Ending balance	11,277.6		8,302.9	7,656.3
Patent and others [member] | Accumulated amortization [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning balance	5,896.4		5,239.1	4,747.5
Additions	1,112.5		658.2	522.5
Disposals or retirements				(31.2)
Effect of exchange rate changes			(0.9)	0.3
Ending balance	$ 7,008.9		$ 5,896.4	$ 5,239.1

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of reconciliation of changes in intangible assets and goodwill [abstract]
Annual discount rate	8.00%	8.00%
Impairment loss recognized in goodwill	$ 0	$ 0	$ 0

Short-term Loans - Summary of S

Short-term Loans - Summary of Short-term Loans (Detail) € in Millions, $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2020EUR (€)	Dec. 31, 2019USD ($)	Dec. 31, 2019EUR (€)
Disclosure of detailed information about borrowings [line items]
Amount	$ 88,559	$ 118,522.3	$ 3,153.8
Loan content			$ 200	€ 2,398	$ 2,370	€ 1,410
Maturity date	2021-02	2020-05
Bottom of range [member]
Disclosure of detailed information about borrowings [line items]
Annual interest rate	(0.54%)	0.01%	(0.54%)	(0.54%)	0.01%	0.01%
Top of range [member]
Disclosure of detailed information about borrowings [line items]
Annual interest rate	0.33%	2.22%	0.33%	0.33%	2.22%	2.22%
Unsecured Loans [member]
Disclosure of detailed information about borrowings [line items]
Amount	$ 88,559	$ 118,522.3

Bonds Payable - Summary of Bond

Bonds Payable - Summary of Bonds Payable (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Bonds payable [line items]
Less: Current portion	$ (2,600)		$ (31,800)
Noncurrent bonds payable	254,105.1	$ 9,049.3	25,100
Cost [member] | Taiwan [member]
Bonds payable [line items]
Unsecured bonds	173,197		$ 56,900
Cost [member] | Overseas [member]
Bonds payable [line items]
Unsecured bonds	84,291
Discounts on bonds payable [member]
Bonds payable [line items]
Discounts on bonds payable	$ (782.9)

Bonds Payable - Major Terms of

Bonds Payable - Major Terms of Domestic Unsecured Bonds (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)
Domestic Unsecured Bonds Hundred Two [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2012-01
Issuance ending period	2019-01
Coupon Rate	1.46%	1.46%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred Two [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 7,000
Domestic Unsecured Bonds Hundred And One One [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2012-08
Issuance ending period	2019-08
Coupon Rate	1.40%	1.40%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And One One [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 9,000
Domestic Unsecured Bonds Hundred And One Two [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2012-09
Issuance ending period	2019-09
Coupon Rate	1.39%	1.39%
Domestic unsecured bonds	$ 9,000
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And One Three [member]
Bonds payable [line items]
Issuance starting period	2012-10
Issuance ending period	2022-10
Coupon Rate	1.53%	1.53%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And One Three [member] | Taiwan [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 4,400
Domestic Unsecured Bonds Hundred And One Four [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2013-01
Issuance ending period	2020-01
Coupon Rate	1.35%	1.35%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And One Four [member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2013-01
Issuance ending period	2023-01
Coupon Rate	1.49%	1.49%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And One Four [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 10,000
Domestic Unsecured Bonds Hundred And One Four [member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 3,000
Domestic Unsecured Bonds Hundred And Two One [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2013-02
Issuance ending period	2020-02
Coupon Rate	1.38%	1.38%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two One [member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2013-02
Issuance ending period	2023-02
Coupon Rate	1.50%	1.50%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two One [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 11,600
Domestic Unsecured Bonds Hundred And Two One [member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 3,600
Domestic Unsecured Bonds Hundred And Two Two [member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2013-07
Issuance ending period	2020-07
Coupon Rate	1.50%	1.50%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two Two [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2013-07
Issuance ending period	2023-07
Coupon Rate	1.70%	1.70%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two Two [member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 10,200
Domestic Unsecured Bonds Hundred And Two Two [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 3,500
Domestic Unsecured Bonds Hundred And Two Three [member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2013-08
Issuance ending period	2019-08
Coupon Rate	1.52%	1.52%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two Three [member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 8,500
Domestic Unsecured Bonds Hundred And Two Four [member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2013-09
Issuance ending period	2019-03
Coupon Rate	1.60%	1.60%
Repayment and Interest Payment	Bullet repayment; interest payable annually (interest for the six months prior to maturity will accrue on the basis of actual days and be repayable at maturity)
Domestic Unsecured Bonds Hundred And Two Four [member] | Tranche D [member]
Bonds payable [line items]
Issuance starting period	2013-09
Issuance ending period	2021-03
Coupon Rate	1.85%	1.85%
Repayment and Interest Payment	Bullet repayment; interest payable annually (interest for the six months prior to maturity will accrue on the basis of actual days and be repayable at maturity)
Domestic Unsecured Bonds Hundred And Two Four [member] | Tranche E [member]
Bonds payable [line items]
Issuance starting period	2013-09
Issuance ending period	2023-03
Coupon Rate	2.05%	2.05%
Repayment and Interest Payment	Bullet repayment; interest payable annually (interest for the six months prior to maturity will accrue on the basis of actual days and be repayable at maturity)
Domestic Unsecured Bonds Hundred And Two Four [member] | Tranche F [member]
Bonds payable [line items]
Issuance starting period	2013-09
Issuance ending period	2023-09
Coupon Rate	2.10%	2.10%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Two Four [member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 1,400
Domestic Unsecured Bonds Hundred And Two Four [member] | Taiwan [member] | Tranche D [member]
Bonds payable [line items]
Domestic unsecured bonds	2,600
Domestic Unsecured Bonds Hundred And Two Four [member] | Taiwan [member] | Tranche E [member]
Bonds payable [line items]
Domestic unsecured bonds	5,400
Domestic Unsecured Bonds Hundred And Two Four [member] | Taiwan [member] | Tranche F [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 2,600
Domestic Unsecured Bonds Hundred And Nine One [Member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2060-09
Coupon Rate	2.70%	2.70%
Repayment and Interest Payment	Bullet repayment (callable on the 5th anniversary of the issue date and every anniversary thereafter); interest payable annually
Domestic Unsecured Bonds Hundred And Nine One [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-03
Issuance ending period	2025-03
Coupon Rate	0.58%	0.58%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine One [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-03
Issuance ending period	2027-03
Coupon Rate	0.62%	0.62%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine One [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-03
Issuance ending period	2030-03
Coupon Rate	0.64%	0.64%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine One [Member] | Taiwan [member]
Bonds payable [line items]
Domestic unsecured bonds		$ 1,000
Domestic Unsecured Bonds Hundred And Nine One [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 3,000
Domestic Unsecured Bonds Hundred And Nine One [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	10,500
Domestic Unsecured Bonds Hundred And Nine One [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 10,500
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-04
Issuance ending period	2025-04
Coupon Rate	0.52%	0.52%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-04
Issuance ending period	2027-04
Coupon Rate	0.58%	0.58%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-04
Issuance ending period	2030-04
Coupon Rate	0.60%	0.60%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 5,900
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	10,400
Domestic Unsecured Bonds Hundred And Nine Two [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 5,300
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-05
Issuance ending period	2025-05
Coupon Rate	0.55%	0.55%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-05
Issuance ending period	2027-05
Coupon Rate	0.60%	0.60%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-05
Issuance ending period	2030-05
Coupon Rate	0.64%	0.64%
Repayment and Interest Payment	Bullet repayment; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 4,500
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	7,500
Domestic Unsecured Bonds Hundred And Nine Three [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 2,400
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-07
Issuance ending period	2025-07
Coupon Rate	0.58%	0.58%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-07
Issuance ending period	2027-07
Coupon Rate	0.65%	0.65%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-07
Issuance ending period	2030-07
Coupon Rate	0.67%	0.67%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 5,700
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	6,300
Domestic Unsecured Bonds Hundred And Nine Four [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 1,900
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2025-09
Coupon Rate	0.50%	0.50%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2027-09
Coupon Rate	0.58%	0.58%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2030-09
Coupon Rate	0.60%	0.60%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 4,800
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	8,000
Domestic Unsecured Bonds Hundred And Nine Five [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 2,800
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2025-12
Coupon Rate	0.40%	0.40%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2027-12
Coupon Rate	0.44%	0.44%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2030-12
Coupon Rate	0.48%	0.48%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 1,600
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	5,600
Domestic Unsecured Bonds Hundred And Nine Six [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 4,800
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Tranche A [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2025-12
Coupon Rate	0.36%	0.36%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Tranche B [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2027-12
Coupon Rate	0.41%	0.41%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Tranche C [member]
Bonds payable [line items]
Issuance starting period	2020-12
Issuance ending period	2030-12
Coupon Rate	0.45%	0.45%
Repayment and Interest Payment	Two equal installments in last two years; interest payable annually
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Taiwan [member] | Tranche A [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 1,900
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Taiwan [member] | Tranche B [member]
Bonds payable [line items]
Domestic unsecured bonds	10,200
Domestic Unsecured Bonds Hundred And Nine Seven [Member] | Taiwan [member] | Tranche C [member]
Bonds payable [line items]
Domestic unsecured bonds	$ 6,400

Bonds Payable - Major Terms o_2

Bonds Payable - Major Terms of Overseas Unsecured Bonds (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Overseas [member] | Issuance period one [Member]
Bonds payable [line items]
Overseas unsecured bonds	$ 1,000
Overseas [member] | Issuance period two [Member]
Bonds payable [line items]
Overseas unsecured bonds	750
Overseas [member] | Issuance period three [Member]
Bonds payable [line items]
Overseas unsecured bonds	$ 1,250
Overseas unsecured bonds [member] | Issuance period one [Member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2025-09
Coupon Rate	0.75%
Repayment and Interest Payment	Bullet repayment (callable at any time, in whole or in part, at the relevant redemption price according to relevant agreements); interest payable semi-annually
Overseas unsecured bonds [member] | Issuance period two [Member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2027-09
Coupon Rate	1.00%
Repayment and Interest Payment	Bullet repayment (callable at any time, in whole or in part, at the relevant redemption price according to relevant agreements); interest payable semi-annually
Overseas unsecured bonds [member] | Issuance period three [Member]
Bonds payable [line items]
Issuance starting period	2020-09
Issuance ending period	2030-09
Coupon Rate	1.375%
Repayment and Interest Payment	Bullet repayment (callable at any time, in whole or in part, at the relevant redemption price according to relevant agreements); interest payable semi-annually

Long-Term Bank Loans - Summary

Long-Term Bank Loans - Summary of Loans and Bonds Payable (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)
Disclosure of detailed information about borrowings [line items]
Long-term bank loans	$ 1,967.6	$ 70.1
Long-term bank loans [member]
Disclosure of detailed information about borrowings [line items]
Unsecured loans	2,000
Less: Discounts on government grants	(32.4)
Long-term bank loans	$ 1,967.6
Annual interest rate	0.40%	0.40%
Maturity date	September 2025

Retirement Benefit Plans - Addi

Retirement Benefit Plans - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2021
Disclosure of defined benefit plans [line items]
Employer contribution percentage, defined contribution plans	6.00%
Defined contribution plans expense	$ 2,809.5	$ 2,609.7	$ 2,568.9
Employer contribution percentage, defined benefit plans	2.00%
Defined benefit plans contribution in the next year	$ 229.9
Weighted average duration of the defined benefit obligation	9 years
Future salary increase rate (2021)	3.00%	3.00%
Forecast [Member]
Disclosure of defined benefit plans [line items]
Future salary increase rate (2021)				20.00%
Actuarial assumption of discount rates [member]
Disclosure of defined benefit plans [line items]
Amount of increase in defined benefit obligation	$ 694.7	$ 725
Actuarial assumption of expected rates of salary increases [member]
Disclosure of defined benefit plans [line items]
Percentage of increase in salary rate	0.50%
Amount of increase in defined benefit obligation	$ 836	$ 706.5
Maximum [Member] | Actuarial assumption of discount rates [member]
Disclosure of defined benefit plans [line items]
Percentage after decrease in discount rate	0.50%
Minimum [Member] | Actuarial assumption of discount rates [member]
Disclosure of defined benefit plans [line items]
Percentage after decrease in discount rate	0.00%

Retirement Benefit Plans - Amou

Retirement Benefit Plans - Amounts Recognized in Consolidated Statements of Profit or Loss and Other Comprehensive Income of Defined Benefit Plans (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of defined benefit plans [abstract]
Current service cost	$ 123.3		$ 135.6	$ 137.7
Net interest expense	81.6		124	144.1
Components of defined benefit costs recognized in profit or loss	204.9		259.6	281.8
Remeasurement on the net defined benefit liability:
Return on plan assets (excluding amounts included in net interest expense)	(139.2)		(124.4)	(71.3)
Actuarial loss (gain) arising from experience adjustments	494.1		(438)	334.7
Actuarial gain arising from changes in demographic assumptions			(233.2)
Actuarial loss arising from changes in financial assumptions	3,161.9		541.7	597.8
Components of defined benefit costs recognized in other comprehensive income	3,516.8	$ 125.2	(253.9)	861.2
Total	$ 3,721.7		$ 5.7	$ 1,143

Retirement Benefit Plans - Pens

Retirement Benefit Plans - Pension Costs of Defined Benefit Plans Recognized in Profit or Loss by Categories (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of defined benefit plans [line items]
Defined benefit cost recognized in the income statement	$ 204.9	$ 259.6	$ 281.8
Cost of revenue [member]
Disclosure of defined benefit plans [line items]
Defined benefit cost recognized in the income statement	126.3	157.8	177.8
Research and development expenses [member]
Disclosure of defined benefit plans [line items]
Defined benefit cost recognized in the income statement	57.3	72.7	79.1
General and administrative expenses [member]
Disclosure of defined benefit plans [line items]
Defined benefit cost recognized in the income statement	18.2	25.1	20.6
Marketing expenses [member]
Disclosure of defined benefit plans [line items]
Defined benefit cost recognized in the income statement	$ 3.1	$ 4	$ 4.3

Retirement Benefit Plans - Am_2

Retirement Benefit Plans - Amounts Arising from Defined Benefit Obligation in Consolidated Statements of Financial Position (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Disclosure of defined benefit plans [abstract]
Present value of defined benefit obligation	$ 16,980.3		$ 13,484.1
Fair value of plan assets	(5,066.2)		(4,301.6)
Net defined benefit liability	$ 11,914.1	$ 424.3	$ 9,182.5

Retirement Benefit Plans - Move

Retirement Benefit Plans - Movements in Present Value of Defined Benefit Obligation (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Remeasurement:
Actuarial loss (gain) arising from experience adjustments	$ 494.1	$ (438)	$ 334.7
Actuarial gain arising from changes in demographic assumptions		(233.2)
Actuarial loss arising from changes in financial assumptions	3,161.9	541.7	597.8
Present value of defined benefit obligation [member]
Disclosure of defined benefit plans [line items]
Balance, beginning of year	13,484.1	13,662.7	12,774.6
Current service cost	123.3	135.6	137.7
Interest expense	118.8	175.4	207.8
Remeasurement:
Actuarial loss (gain) arising from experience adjustments	494.1	(438)	334.7
Actuarial gain arising from changes in demographic assumptions		(233.2)
Actuarial loss arising from changes in financial assumptions	3,161.9	541.7	597.8
Benefits paid from plan assets	(399)	(344.1)	(274.3)
Benefits paid directly by the Company	(2.9)	(16)	(115.6)
Balance, end of year	$ 16,980.3	$ 13,484.1	$ 13,662.7

Retirement Benefit Plans - Mo_2

Retirement Benefit Plans - Movements in Fair Value of Plan Assets (Detail) - Fair value of plan assets [member] - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of fair value of plan assets [line items]
Balance, beginning of year	$ 4,301.6	$ 4,011.3	$ 3,923.9
Interest income	37.2	51.4	63.7
Remeasurement:
Return on plan assets (excluding amounts included in net interest expense)	139.2	124.4	71.3
Contributions from employer	987.2	458.6	226.7
Benefits paid from plan assets	(399)	(344.1)	(274.3)
Balance, end of year	$ 5,066.2	$ 4,301.6	$ 4,011.3

Retirement Benefit Plans - Fair

Retirement Benefit Plans - Fair Value of Plan Assets by Major Categories (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of fair value of plan assets [abstract]
Cash	$ 632.8	$ 713.2
Equity instruments	2,926.7	2,313.8
Debt instruments	1,506.7	1,274.6
Fair value of plan assets	$ 5,066.2	$ 4,301.6

Retirement Benefit Plans - Prin

Retirement Benefit Plans - Principal Assumptions for Actuarial Valuation of Present Value of Defined Benefit Obligation (Detail)	Dec. 31, 2020	Dec. 31, 2019
Disclosure of defined benefit plans [abstract]
Discount rate	0.40%	0.90%
Future salary increase rate	3.00%	3.00%

Guarantee Deposits - Summary of

Guarantee Deposits - Summary of Guarantee Deposits (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Guarantee deposits [abstract]
Capacity guarantee			$ 1,499.4
Others	$ 350		230.5
Guarantee deposits	350		1,729.9
Current portion (classified under accrued expenses and other current liabilities)	84.4		1,553
Noncurrent portion	265.6	$ 9.5	176.9
Guarantee deposits	$ 350		$ 1,729.9

Equity - Summary of Capital Sto

Equity - Summary of Capital Stock (Detail) shares in Millions, $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019TWD ($)shares
Disclosure of classes of share capital [abstract]
Authorized shares	28,050	28,050	28,050
Authorized capital | $	$ 280,500		$ 280,500
Issued and paid shares	25,930.3	25,930.3	25,930.3
Issued capital	$ 259,303.8	$ 9,234.5	$ 259,303.8

Equity - Additional Information

Equity - Additional Information (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2020$ / sharesshares	Dec. 31, 2019shares
Disclosure of classes of share capital [line items]
Common shares par value | $ / shares	$ 10
Shares allocated for exercise of employee stock options	500,000,000
Issued capital	25,930.3	25,930.3
Legal capital reserve percentage	10.00%
Percentage of paid in capital on reserve used to offset deficit or distribute as dividend in cash or stock	25.00%
Top of range [member]
Disclosure of classes of share capital [line items]
Total distribution	50.00%
American Depositary Shares (one represents five common shares) [member]
Disclosure of classes of share capital [line items]
Issued capital	1,064.4
Number of shares issued	5,321.8

Equity - Summary of Capital Sur

Equity - Summary of Capital Surplus (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Equity [abstract]
Additional paid-in capital	$ 24,185		$ 24,185
From merger	22,804.5		22,804.5
From convertible bonds	8,892.9		8,892.9
From share of changes in equities of subsidiaries	121.8		121.8
From share of changes in equities of associates	302.5		302.2
Donations	40.5		33.3
Total	$ 56,347.2	$ 2,006.7	$ 56,339.7

Equity - Appropriations of Earn

Equity - Appropriations of Earnings and Dividends Per Share (Detail) $ / shares in Units, $ in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020TWD ($)$ / shares	Sep. 30, 2020TWD ($)$ / shares	Jun. 30, 2020TWD ($)$ / shares	Mar. 31, 2020TWD ($)$ / shares	Dec. 31, 2019TWD ($)$ / shares	Sep. 30, 2019TWD ($)$ / shares	Jun. 30, 2019TWD ($)$ / shares	Mar. 31, 2019TWD ($)$ / shares	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)	Dec. 31, 2020USD ($)
Resolution date of TSMC's Board of Directors in its meeting									Feb. 9, 2021	Feb. 11, 2020	Feb. 19, 2019
Special capital reserve	$ 311,147				$ 311,147				$ 311,147	$ 311,147		$ 11,080.7
Cash dividends to shareholders											$ 8
Cash dividends to shareholders | $ / shares	$ 2.5	$ 2.5	$ 2.5	$ 2.5	$ 2.5	$ 2.5	$ 2.5	$ 2
Appropriation of earnings [member]
Resolution date of TSMC's Board of Directors in its meeting	Feb. 9, 2021	Nov. 10, 2020	Aug. 11, 2020	May 12, 2020	Feb. 11, 2020	Nov. 12, 2019	Aug. 13, 2019	Jun. 5, 2019
Legal capital reserve											35,113.1
Special capital reserve	$ 12,420.7	$ 5,501.3	$ 11,884.5	$ (2,694.8)	$ 16,893	$ 3,289.2	$ (3,338.2)	$ (4,724)	$ 12,420.7	$ 16,893	(11,459.5)
Cash dividends to shareholders	$ 64,826	$ 64,826	$ 64,826	$ 64,826	$ 64,826	$ 64,826	$ 64,826	$ 51,860.8			$ 207,443

Equity - Changes in Other Reser

Equity - Changes in Other Reserves (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Balance, beginning of year	$ (27,568.3)		$ (15,449.9)	$ (27,228.7)
Exchange differences arising on translation of foreign operations	(29,846.8)		(14,693.5)	14,562
Equity instruments	423.2		334.5	(3,311.6)
Debt instruments	3,907		3,097.3	(1,858)
Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal	108.7		(162.1)	1,193.1
Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal	(1,439.4)		(537.8)	989.1
Loss allowance adjustments from debt instruments	(0.9)		6.9	(2)
Gain (loss) arising on changes in the fair value of hedging instruments	24.1		(109.6)	41
Transferred to initial carrying amount of hedged items	(20.3)		82.3	(22.2)
Share of other comprehensive income (loss) of associates	(267.9)		(152)	86.5
Share of unearned stock-based employee compensation of associates	0.2		1.6	8.5
Other comprehensive loss reclassified to profit or loss upon disposal of associates			4.6
Income tax effect	0.6		9.4	92.4
Balance, end of year	(54,679.8)	$ (1,947.3)	(27,568.3)	(15,449.9)
Others - Foreign Currency Translation Reserve [member]
Balance, beginning of year	(26,871.4)		(12,042.4)	(26,697.7)
Exchange differences arising on translation of foreign operations	(29,846.8)		(14,693.5)	14,562
Share of other comprehensive income (loss) of associates	(283.4)		(140.1)	93.3
Other comprehensive loss reclassified to profit or loss upon disposal of associates			4.6
Balance, end of year	(57,001.6)		(26,871.4)	(12,042.4)
Others - Stock-Based Employee Compensation [member]
Balance, beginning of year	(0.2)		(1.8)	(10.3)
Share of unearned stock-based employee compensation of associates	0.2		1.6	8.5
Income tax effect
Balance, end of year			(0.2)	(1.8)
Unrealized gain (loss) on financial assets at fair value through other comprehensive income [member]
Balance, beginning of year	(692.9)		(3,429.3)	(524.9)
Equity instruments	423.2		334.5	(3,311.6)
Debt instruments	3,907		3,097.3	(1,858)
Cumulative unrealized gain (loss) of equity instruments transferred to retained earnings due to disposal	108.7		(162.1)	1,193.1
Cumulative unrealized gain (loss) of debt instruments transferred to profit or loss due to disposal	(1,439.4)		(537.8)	989.1
Loss allowance adjustments from debt instruments	(0.9)		6.9	(2)
Share of other comprehensive income (loss) of associates	15.5		(11.8)	(6.8)
Income tax effect	0.6		9.4	91.8
Balance, end of year	2,321.8		(692.9)	(3,429.3)
Other - Gain (loss) on hedging instruments [member]
Balance, beginning of year	(3.8)		23.6	4.2
Gain (loss) arising on changes in the fair value of hedging instruments	24.1		(109.6)	41
Transferred to initial carrying amount of hedged items	$ (20.3)		82.3	(22.2)
Share of other comprehensive income (loss) of associates			(0.1)
Income tax effect				0.6
Balance, end of year			$ (3.8)	$ 23.6

Net Revenue - Summary of Disagg

Net Revenue - Summary of Disaggregation of Revenue from Contracts with Customers by Product (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 1,339,254.8	$ 1,069,985.4	$ 1,031,473.6
Wafer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	1,178,456.3	927,317.3	911,296.4
Other Products [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 160,798.5	$ 142,668.1	$ 120,177.2

Net Revenue - Summary of Disa_2

Net Revenue - Summary of Disaggregation of Revenue from Contracts with Customers by Geographical Location (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 1,339,254.8	$ 1,069,985.4	$ 1,031,473.6
Taiwan [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	129,082.9	84,255.2	78,260.8
United States [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	817,911	634,713	632,821.5
China [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	233,783.3	208,101.4	175,794.2
Europe Middle East and Africa [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	70,213.4	67,568.2	71,068.5
Japan [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	63,299.2	57,468.6	58,125.9
Other country [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 24,965	$ 17,879	$ 15,402.7

Net Revenue - Summary of Disa_3

Net Revenue - Summary of Disaggregation of Revenue from Contracts with Customers Based on Platform Type (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 1,339,254.8	$ 1,069,985.4	$ 1,031,473.6
Smartphone [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	645,303.6	523,612.9	466,452.3
High performance computing [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	439,810	315,822.3	341,910.2
Internet of things [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	110,355.2	86,342.7	65,091.3
Automotive [Member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	44,367.5	47,914.5	51,709.8
Digital consumer electronics [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	54,555.7	53,733.4	58,470.2
Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 44,862.8	$ 42,559.6	$ 47,839.8

Net Revenue - Summary of Disa_4

Net Revenue - Summary of Disaggregation of Revenue from Contracts with Customers Based on Resolution (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 1,339,254.8	$ 1,069,985.4	$ 1,031,473.6
Wafer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	1,178,456.3	927,317.3	911,296.4
Wafer [member] | 5-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	90,934.5
Wafer [member] | 7-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	394,837	249,548.1	81,680.7
Wafer [member] | 10-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	3,403.1	23,266.4	96,989.5
Wafer [member] | 16-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	197,959	186,700.9	187,370.6
Wafer [member] | 20-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	8,450.9	9,535.8	23,618.4
Wafer [member] | 28-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	149,367.7	149,578.7	178,440.4
Wafer [member] | 40/45-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	103,176.5	93,366.3	101,801
Wafer [member] | 65-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	61,226.7	69,250	76,122.3
Wafer [member] | 90-nanometer [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	29,380.4	25,624.2	36,652.1
Wafer [member] | 0.11/0.13 micron [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	33,197.1	22,947.3	20,677.7
Wafer [member] | 0.15/0.18 micron [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	86,008.5	77,564.5	81,182.6
Wafer [member] | 0.25 micron and above [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	$ 20,514.9	$ 19,935.1	$ 26,761.1

Net Revenue - Summary of Contra

Net Revenue - Summary of Contract Balances (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Accrued expenses and other current liabilities [member]
Disclosure of contract liabilities [line items]
Contract liabilities (classified under accrued expenses and other current liabilities)	$ 13,775.1	$ 6,784.3	$ 4,684

Net Revenue - Additional Inform

Net Revenue - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of refund liabilities [line items]
Revenue from contracts with customers	$ 1,339,254.8	$ 1,069,985.4	$ 1,031,473.6
Accrued expenses and other current liabilities [member]
Disclosure of refund liabilities [line items]
Revenue from contracts with customers	4,737.9	3,876.6	31,770
Estimated sales returns and other allowances	40,453.1	36,211.4	$ 55,406
Refund liabilities	$ 33,194.8	$ 19,620.2

Interest Income - Summary of in

Interest Income - Summary of interest income (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Text Block [Abstract]
Bank deposits	$ 5,139.1		$ 11,454	$ 10,310.7
Financial assets at FVTPL	2.5		339.5	382.7
Financial assets at FVTOCI	3,121.9		3,476.2	3,078.6
Financial assets at amortized cost	754.9		919.7	922.4
Interest income	$ 9,018.4	$ 321.2	$ 16,189.4	$ 14,694.4

Finance Costs - Summary of Fina

Finance Costs - Summary of Finance Costs (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Material income and expense [abstract]
Interest expense, Bank loans	$ 500.9		$ 1,869.4	$ 1,417.3
Interest expense, Corporate bonds	1,337.3		1,139.9	1,633.8
Lease liabilities	227.8		240.9
Interest expense, Others	15.5		0.7	0.1
Finance costs	$ 2,081.5	$ 74.1	$ 3,250.9	$ 3,051.2

Other Gains and Losses - Summar

Other Gains and Losses - Summary of Other Gains and Losses, Net (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Gain (loss) on disposal of financial assets, net
Investments in debt instruments at FVTOCI	$ 1,439.4	$ 51.3	$ 537.8	$ (989.1)
Loss on disposal of subsidiaries			(4.6)
Gain (loss) on financial instruments at FVTPL, net
Mandatorily measured at FVTPL	8,244.5		(2,360.7)	(2,293.9)
Gain (loss) arising from fair value hedges, net			13.1	(2.3)
The reversal (accrual) of expected credit loss of financial assets
Investments in debt instruments at FVTOCI	0.9		(6.9)	2
Financial assets at amortized cost	(4.6)		5.2	0.4
Other gains (losses), net	426.2		665.1	(127.9)
Other gains and losses	$ 10,106.4	$ 360	$ (1,151)	$ (3,410.8)

Income Tax - Summary of Income

Income Tax - Summary of Income Tax Expense (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Current income tax expense
Current tax expense recognized in the current year	$ 87,452.7		$ 47,135.5	$ 60,584.3
Income tax adjustments on prior years	(7,589.4)		(10,193.8)	(21,753)
Other income tax adjustments	150.2		(41.5)	152.9
Current income tax expense	80,013.5		36,900.2	38,984.2
Deferred income tax benefit
Effect of tax rate changes				(1,474.8)
The origination and reversal of temporary differences	(6,275.2)		(1,065.1)	(3,072.5)
Deferred income tax benefit	(6,275.2)		(1,065.1)	(4,547.3)
Income tax expense recognized in profit or loss	$ 73,738.3	$ 2,626	$ 35,835.1	$ 34,436.9

Income Tax - Reconciliation of

Income Tax - Reconciliation of Income before Income Tax and Income Tax Expense Recognized in Profit or Loss (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Reconciliation of accounting profit multiplied by applicable tax rates [abstract]
Income before tax	$ 584,746.3		$ 389,862.1	$ 397,543.1
Income tax expense at the statutory rate	118,831.3		79,056.5	80,872.5
Tax effect of adjusting items:
Nondeductible (deductible) items in determining taxable income	1,015.9		(4,183.5)	2,533.4
Tax-exempt income	(65,988.1)		(39,808.1)	(54,543.5)
Additional income tax under the Alternative Minimum Tax Act	18,872.8		10,367.9	21,455.9
Additional income tax on unappropriated earnings	14,747.3		7,628.1	16,294.5
Effect of tax rate changes on deferred income tax				(1,474.8)
The origination and reversal of temporary differences	(6,275.2)		(1,065.1)	(3,072.5)
Income tax credits	(26.5)		(5,925.4)	(6,028.4)
Tax effect of adjusting items	81,177.5		46,070.4	56,037
Income tax adjustments on prior years	(7,589.4)		(10,193.8)	(21,753)
Other income tax adjustments	150.2		(41.5)	152.9
Income tax expense recognized in profit or loss	$ 73,738.3	$ 2,626	$ 35,835.1	$ 34,436.9

Income Tax - Additional Informa

Income Tax - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Disclosure Of Income Taxes [line items]
Aggregate deductible temporary differences for which no deferred income tax assets recognized	$ 33,445.5		$ 55,521
Aggregate taxable temporary differences associated with investments in subsidiaries not recognized as deferred income tax liabilities	$ 131,085.7		$ 152,827.4
Changes in tax rates or tax laws enacted or announced [member]
Disclosure Of Income Taxes [line items]
Percentage of corporate income tax rate	20.00%	17.00%
Percentage of tax rate surtax imposed on unappropriated earnings	5.00%	10.00%

Income Tax - Income Tax Expense

Income Tax - Income Tax Expense Recognized in Other Comprehensive Income (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax relating to components of other comprehensive income [abstract]
Related to remeasurement of defined benefit obligation	$ 422.1	$ (30.4)	$ 103.3
Related to unrealized gain/loss on investments in equity instruments at FVTOCI	0.6	9.4	91.8
Related to gain/loss on cash flow hedges			0.6
Deferred income tax benefit (expense)	$ 422.7	$ (21)	$ 195.7

Income Tax - Analysis of Deferr

Income Tax - Analysis of Deferred Income Tax Assets and Liabilities in Consolidated Statements of Financial Position (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	$ 17,928.4	$ 16,806.4	$ 12,105.5
Recognized in Profit or loss	7,660.7	1,176.2	4,514.6
Recognized in Other Comprehensive Income	422.7	(21)	159.5
Effect of Exchange Rate Changes	(53.6)	(33.2)	26.8
Balance, End of Year	25,958.2	17,928.4	16,806.4
Deferred Income Tax Liabilities [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	(344.4)	(233.3)	(302.2)
Recognized in Profit or loss	(1,385.5)	(111.1)	32.7
Recognized in Other Comprehensive Income			36.2
Balance, End of Year	(1,729.9)	(344.4)	(233.3)
Depreciation [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	13,547.2	11,839.2	8,401.3
Recognized in Profit or loss	5,824	1,727.8	3,430.4
Effect of Exchange Rate Changes	(16.8)	(19.8)	7.5
Balance, End of Year	19,354.4	13,547.2	11,839.2
Refund liability [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	2,150.4	2,594	1,637.7
Recognized in Profit or loss	1,606.1	(443.2)	955
Effect of Exchange Rate Changes	(1.4)	(0.4)	1.3
Balance, End of Year	3,755.1	2,150.4	2,594
Net defined benefit liability [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	1,016.3	1,084.9	975.3
Recognized in Profit or loss	(96.3)	(38.2)	6.3
Recognized in Other Comprehensive Income	422.1	(30.4)	103.3
Balance, End of Year	1,342.1	1,016.3	1,084.9
Unrealized loss on inventories [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	469.4	751	629.5
Recognized in Profit or loss	391.1	(280.8)	120.5
Effect of Exchange Rate Changes	(2)	(0.8)	1
Balance, End of Year	858.5	469.4	751
Deferred compensation cost [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	323.1	271.7	266.5
Recognized in Profit or loss	27.4	59.4	(4.7)
Effect of Exchange Rate Changes	(20.2)	(8)	9.9
Balance, End of Year	330.3	323.1	271.7
Investments in equity instruments at FVTOCI [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	65.7	56.2
Recognized in Profit or loss		0.1
Recognized in Other Comprehensive Income	0.6	9.4	56.2
Balance, End of Year	66.3	65.7	56.2
Investments in equity instruments at FVTOCI [member] | Deferred Income Tax Liabilities [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year			(95.4)
Recognized in Other Comprehensive Income			95.4
Others [member] | Deferred Income Tax Assets [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	356.3	209.4	195.2
Recognized in Profit or loss	(91.6)	151.1	7.1
Effect of Exchange Rate Changes	(13.2)	(4.2)	7.1
Balance, End of Year	251.5	356.3	209.4
Others [member] | Deferred Income Tax Liabilities [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	(10.8)	(171.6)	(37.3)
Recognized in Profit or loss	(852.6)	160.8	(75.1)
Recognized in Other Comprehensive Income			(59.2)
Balance, End of Year	(863.4)	(10.8)	(171.6)
Unrealized exchange gains [member] | Deferred Income Tax Liabilities [Member]
Deferred income tax assets (liabilities)
Balance, Beginning of Year	(333.6)	(61.7)	(169.5)
Recognized in Profit or loss	(532.9)	(271.9)	107.8
Balance, End of Year	$ (866.5)	$ (333.6)	$ (61.7)

Income Tax - Tax-exemption Info

Income Tax - Tax-exemption Information Related to Profits Generated from Certain Projects (Detail) - Construction and expansion of two thousand and nine [member]	12 Months Ended
	Dec. 31, 2020
Disclosure Of Tax Exemption [line items]
Tax-exemption Period, Start	2018
Tax-exemption Period, End	2022

Earnings Per Share - Computatio

Earnings Per Share - Computation of Earnings Per Share (Detail) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)$ / sharesshares	Dec. 31, 2020$ / shares	Dec. 31, 2019TWD ($)$ / sharesshares	Dec. 31, 2018TWD ($)$ / sharesshares
Earnings per share [abstract]
Net income available to common shareholders of the parent | $	$ 510,744		$ 353,948	$ 363,052.7
Net income available to common shareholders of the parent | shares	25,930.3		25,930.3	25,930.3
Basic EPS | (per share)	$ 19.70	$ 0.70	$ 13.65	$ 14
Diluted EPS | (per share)	$ 19.70	$ 0.70	$ 13.65	$ 14

Additional Information of Exp_3

Additional Information of Expenses by Nature - Summary of Additional Information of Expenses by Nature (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Expense by nature [line items]
Other operating income and expenses	$ 710	$ 25.3	$ (496.3)	$ (2,101.5)
Defined contribution plans	2,809.5		2,609.7	2,568.9
Defined benefit plans	204.9		259.6	281.8
Depreciation of property, plant and equipment and right-of-use assets	324,538.4	11,557.6	281,411.8	288,124.9
Amortization of intangible assets	7,186.2	$ 255.9	5,472.4	4,421.4
Post-employment benefits	3,014.4		2,869.3	2,850.7
Depreciation of property, plant and equipment and right-of-use assets [members]
Expense by nature [line items]
Cost of revenue	299,311.4		256,530.9	264,804.7
Operating expenses	25,191.3		24,856.7	23,292.3
Other operating income and expenses	35.7		24.2	27.9
Amortization of intangible assets [members]
Expense by nature [line items]
Cost of revenue	4,837.7		3,069.9	2,073.5
Operating expenses	2,348.5		2,402.5	2,347.9
Employee benefits expenses [members]
Expense by nature [line items]
Cost of revenue	83,099		64,702	63,597.7
Operating expenses	57,718.4		45,282.6	44,617.2
Defined contribution plans	2,809.5		2,609.7	2,568.9
Defined benefit plans	204.9		259.6	281.8
Other employee benefits	137,803		107,115.3	105,364.2
Employee benefits expenses	$ 140,817.4		$ 109,984.6	$ 108,214.9

Additional Information of Exp_4

Additional Information of Expenses by Nature - Summary of Accrued Profit Sharing Bonus to Employees (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Bonus to Employees [member]
Expense by Nature [line items]
Accrued profit sharing bonus to employees	$ 34,753.2	$ 23,165.7	$ 23,570

Additional Information of Exp_5

Additional Information of Expenses by Nature - Summary of Profit Sharing Bonus to Employees and Compensation to Directors (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Expense by Nature [line items]
Resolution date of TSMC's Board of Directors in its meeting	Feb. 9, 2021	Feb. 11, 2020	Feb. 19, 2019
Bonus to Employees [member]
Expense by Nature [line items]
Profit sharing bonus to employees	$ 34,753.2	$ 23,165.7	$ 23,570
Compensation to Directors [member]
Expense by Nature [line items]
Compensation to directors	$ 509.8	$ 360.4	$ 349.3

Additional Information of Exp_6

Additional Information of Expenses by Nature - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Top of range [member] | Compensation to Directors [member]
Expense by nature [line items]
Profit sharing bonus, percentage	0.30%	0.30%	0.30%
Bottom of range [member] | Bonus to Employees [member]
Expense by nature [line items]
Profit sharing bonus, percentage	1.00%	1.00%	1.00%

Cash Flow Information - Schedul

Cash Flow Information - Schedule of Detailed Information about Non Cash Transaction (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of detailed information about non-cash transaction [line items]
Conversion of convertible bonds into equity securities	$ (120.5)			$ (23.8)
Payments for acquisition of financial assets at FVTOCI	262,637.5	$ 9,353.2	$ 257,558.2	96,412.8
Additions of financial assets at FVTOCI	268,653.5		257,824.5	100,759.6
Disposal of financial assets at FVTOCI	269,011.8		229,525.1	90,545.1
Additions of property, plant and equipment	525,720.7		564,283	300,024.4
Exchange of assets	(1.1)		(3,287.1)
Changes in other financial assets	10.5		22.2	22.8
Proceeds from disposal of financial assets at FVTOCI	266,931.9		230,444.5	86,639.3
Changes in payables to contractors and equipment suppliers	(19,085.9)		(100,963.9)	13,979.9
Transferred to initial carrying amount of hedged items	20.3		(82.3)	22.2
Payments for acquisition of property, plant and equipment	507,238.7	18,064.1	460,422.2	315,581.9
Changes in account payable	404.6	14.4	5,860.1	4,540.6
Changes in accrued expenses and other current liabilities	(5,895.5)		(266.3)	(4,323)
Payments for acquisition of intangible assets	9,542.4	$ 339.8	9,329.9	7,100.3
Intangible assets [member]
Disclosure of detailed information about non-cash transaction [line items]
Additions of intangible assets	12,559.5		9,237.7	7,105
Changes in account payable	191.4		70	(27.5)
Changes in accrued expenses and other current liabilities	(3,219)
Financial assets measured at fair value through other comprehensive income, category [member]
Disclosure of detailed information about non-cash transaction [line items]
Changes in other financial assets	(2,079.9)		919.4	(3,905.8)
Payments for acquisition of intangible assets	9,542.4		9,329.9	7,100.3
Property, plant and equipment [member]
Disclosure of detailed information about non-cash transaction [line items]
Changes in other financial assets	$ 584.7		$ 472.5	$ 1,555.4

Cash Flow Information - Sched_2

Cash Flow Information - Schedule of Liabilities Arising From Financing Activities (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance		$ 190,743.7	$ 230,048.5
Financing Cash Flow			(34,381.1)
Non-cash changes Foreign Exchange Movement			1,105.5
Non-cash changes Other Changes			(6,029.2)
Ending Balance			190,743.7
IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	$ 194,469.1	210,647.3
Financing Cash Flow	172,273.2	(6,908.8)
Non-cash changes Foreign Exchange Movement	(3,227)	(2,105.5)
Non-cash changes Lease modifications	7,742.2	419.7
Non-cash changes Other Changes	(1,287.2)	(7,583.6)
Ending Balance	369,970.3	194,469.1	210,647.3
Short-term loans [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance		88,754.7	63,766.8
Financing Cash Flow			23,923
Non-cash changes Foreign Exchange Movement			1,064.9
Ending Balance			88,754.7
Short-term loans [member] | IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	118,522.3	88,754.7
Financing Cash Flow	(31,571.6)	31,804.3
Non-cash changes Foreign Exchange Movement	1,608.3	(2,036.7)
Ending Balance	88,559	118,522.3	88,754.7
Guarantee deposits [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance		10,189	16,080.6
Financing Cash Flow			(279.2)
Non-cash changes Foreign Exchange Movement			423.5
Non-cash changes Other Changes			(6,035.9)
Ending Balance			10,189
Guarantee deposits [member] | IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	1,729.9	10,189
Financing Cash Flow	129.5	(639.1)
Non-cash changes Foreign Exchange Movement	1.8	4.5
Non-cash changes Other Changes	(1,511.2)	(7,824.5)
Ending Balance	350	1,729.9	10,189
Lease Liabilities [member] | IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	17,316.9	19,903.6
Financing Cash Flow	(2,819.7)	(3,174)
Non-cash changes Foreign Exchange Movement	(78.5)	(73.3)
Non-cash changes Lease modifications	7,742.2	419.7
Non-cash changes Other Changes	227.7	240.9
Ending Balance	22,388.6	17,316.9	19,903.6
Bonds payable [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance		91,800	150,201.1
Financing Cash Flow			(58,024.9)
Non-cash changes Foreign Exchange Movement			(382.9)
Non-cash changes Other Changes			6.7
Ending Balance			91,800
Bonds payable [member] | IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	56,900	91,800
Financing Cash Flow	204,535	(34,900)
Non-cash changes Foreign Exchange Movement	(4,758.6)
Non-cash changes Other Changes	28.7
Ending Balance	256,705.1	$ 56,900	$ 91,800
Long-term bank loans [member] | IFRS 16 [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Financing Cash Flow	2,000
Non-cash changes Other Changes	(32.4)
Ending Balance	$ 1,967.6

Financial Instruments - Categor

Financial Instruments - Categories of Financial Instruments (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Financial assets
FVTPL (Note 1)	$ 2,259.4		$ 326.8
FVTOCI (Note 2)	129,918.7		134,776.8
Hedging financial assets	0.1		25.9
Amortized cost (Note 3)	826,293.6		612,740.6
Financial assets	958,471.8		747,870.1
Financial liabilities
FVTPL (Note 4)	94.1		982.3
Hedging financial liabilities	1.2	$ 0.1	1.8
Amortized cost (Note 5)	748,129.3		533,581.7
Financial liabilities	$ 748,224.6		$ 534,565.8

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of detailed information about financial instruments [line items]
Increase decrease in fixed income investment fair value	$ (3,143.6)	$ (3,517.4)	$ (2,697.8)
Percentage of accounts receivable from ten largest customers	79.00%	79.00%
Expected credit loss decrease increase	$ 1.1	$ 0.6	$ (1.1)
Level 3 [member]
Disclosure of detailed information about financial instruments [line items]
Discount for lack of marketability percentage	10.00%	10.00%
Decrease in fair value due to lack of marketability increase by 1%	$ (39)	$ (34.8)
Percentage increase in the discount for lack of marketability	1.00%	1.00%
Equity Price Risk [member]
Disclosure of detailed information about financial instruments [line items]
Assumed change in risk	(10.00%)	(10.00%)	(10.00%)
Assumed change in risk, monetary effect	$ (446.5)	$ (401.9)	$ (427.1)
Currency Risk [member]
Disclosure of detailed information about financial instruments [line items]
Assumed change in risk	(10.00%)	(10.00%)	(10.00%)
Assumed change in risk, monetary effect	$ (897.7)	$ (2,137.3)	$ (506.4)
Currency Risk [member] | Other comprehensive income [member]
Disclosure of detailed information about financial instruments [line items]
Assumed change in risk, monetary effect		$ (107.7)	$ (315.6)
Interest rate risk [member] | Fixed Income Securities [member]
Disclosure of detailed information about financial instruments [line items]
Assumed change in risk	1.00%	1.00%	1.00%
Assumed change in risk, monetary effect	$ (3,143.6)	$ (3,516.6)	$ (2,450)
Decrease in net income		$ (0.8)	$ (247.8)

Financial Instruments - Summary

Financial Instruments - Summary of Current Credit Risk Assessment Policies (Detail) - Credit risk [member]	12 Months Ended
	Dec. 31, 2020
Write-off [member]
Disclosure of credit risk exposure [line items]
Description	There is evidence indicating that the debtor is in severe financial difficulty and the Company has no realistic prospect of recovery
Basis for Recognizing Expected Credit Loss	Amount is written off
12-month expected credit losses [member] | Performing [member]
Disclosure of credit risk exposure [line items]
Description	Credit rating is investment grade on valuation date
Basis for Recognizing Expected Credit Loss	12 months expected credit loss
Lifetime expected credit losses [member] | Doubtful [member]
Disclosure of credit risk exposure [line items]
Description	Credit rating is non-investment grade on valuation date
Basis for Recognizing Expected Credit Loss	Lifetime expected credit loss-not credit impaired
Lifetime expected credit losses [member] | In default [member]
Disclosure of credit risk exposure [line items]
Description	Credit rating is CC or below on valuation date
Basis for Recognizing Expected Credit Loss	Lifetime expected credit loss-credit impaired
Minimum [Member] | 12-month expected credit losses [member] | Performing [member]
Disclosure of credit risk exposure [line items]
Expected Credit Loss Ratio	0.00%
Maximum [Member] | 12-month expected credit losses [member] | Performing [member]
Disclosure of credit risk exposure [line items]
Expected Credit Loss Ratio	0.10%

Financial Instruments - Summa_2

Financial Instruments - Summary of Maturity Profile of Financial Liabilities Based on Contractual Undiscounted Payments, Including Principal and Interest (Detail) $ in Millions, $ in Millions	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)
Disclosure of detailed information about financial instruments [line items]
Short-term loans	$ 88,559	$ 3,153.8	$ 118,522.3
Accrued expenses and other current liabilities	87,683.2	3,122.6	56,373.2
Long-term bank loans	1,967.6	$ 70.1
Total non-derivative and derivative financial instruments	682,091.8		424,402.4
Non-derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Short-term loans	88,557.5		118,562.6
Accounts payable (including related parties)	41,095		40,206
Payables to contractors and equipment suppliers	157,805		140,810.7
Accrued expenses and other current liabilities	71,995.7		45,760.9
Bonds payable	300,098.5		58,320.2
Long-term bank loans	2,026.3
Lease liabilities (including those classified under accrued expenses and other current liabilities)	23,857.6		18,690.2
Guarantee deposits (including those classified under accrued expenses and other current liabilities)	350		1,729.9
Non-derivative financial liabilities	685,785.6		424,080.5
Derivative financial instruments [member] | Forward exchange contracts [member]
Disclosure of detailed information about financial instruments [line items]
Outflows	177,764.2		141,450.8
Inflows	(181,458)		(141,128.9)
Derivative financial instruments	(3,693.8)		321.9
Less than 1 year [member]
Disclosure of detailed information about financial instruments [line items]
Total non-derivative and derivative financial instruments	363,204		382,029.1
Less than 1 year [member] | Non-derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Short-term loans	88,557.5		118,562.6
Accounts payable (including related parties)	41,095		40,206
Payables to contractors and equipment suppliers	157,805		140,810.7
Accrued expenses and other current liabilities	71,995.7		45,760.9
Bonds payable	5,328		32,338.9
Long-term bank loans	8
Lease liabilities (including those classified under accrued expenses and other current liabilities)	2,024.2		2,475.1
Guarantee deposits (including those classified under accrued expenses and other current liabilities)	84.4		1,553
Non-derivative financial liabilities	366,897.8		381,707.2
Less than 1 year [member] | Derivative financial instruments [member] | Forward exchange contracts [member]
Disclosure of detailed information about financial instruments [line items]
Outflows	177,764.2		141,450.8
Inflows	(181,458)		(141,128.9)
Derivative financial instruments	(3,693.8)		321.9
1-3 years [member]
Disclosure of detailed information about financial instruments [line items]
Total non-derivative and derivative financial instruments	32,159.2		10,681.6
1-3 years [member] | Non-derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Bonds payable	27,631.6		7,777.7
Long-term bank loans	847.4
Lease liabilities (including those classified under accrued expenses and other current liabilities)	3,566.7		2,782.9
Guarantee deposits (including those classified under accrued expenses and other current liabilities)	113.5		121
Non-derivative financial liabilities	32,159.2		10,681.6
3-5 years [member]
Disclosure of detailed information about financial instruments [line items]
Total non-derivative and derivative financial instruments	64,508.3		20,743.6
3-5 years [member] | Non-derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Bonds payable	59,986.8		18,203.6
Long-term bank loans	1,170.9
Lease liabilities (including those classified under accrued expenses and other current liabilities)	3,198.8		2,484.5
Guarantee deposits (including those classified under accrued expenses and other current liabilities)	151.8		55.5
Non-derivative financial liabilities	64,508.3		20,743.6
More than 5 years [member]
Disclosure of detailed information about financial instruments [line items]
Total non-derivative and derivative financial instruments	222,220.3		10,948.1
More than 5 years [member] | Non-derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Bonds payable	207,152.1
Lease liabilities (including those classified under accrued expenses and other current liabilities)	15,067.9		10,947.7
Guarantee deposits (including those classified under accrued expenses and other current liabilities)	0.3		0.4
Non-derivative financial liabilities	$ 222,220.3		$ 10,948.1

Financial Instruments - Detaile

Financial Instruments - Detailed Information About In Maturity Analysis For Lease Liabilities (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Lease liabilities	$ 15,067.9	$ 10,947.7
5-10 years [member]
Disclosure of detailed information about financial instruments [line items]
Lease liabilities	7,402	5,581.1
10-15 years [member]
Disclosure of detailed information about financial instruments [line items]
Lease liabilities	5,253.9	3,691.3
15-20 years [member]
Disclosure of detailed information about financial instruments [line items]
Lease liabilities	2,255.2	1,600.9
More than 20 years [member]
Disclosure of detailed information about financial instruments [line items]
Lease liabilities	$ 156.8	$ 74.4

Financial Instruments - Fair Va

Financial Instruments - Fair Value of Financial Instruments Measured at Fair Value on a Recurring Basis (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL	$ 2,259.4	$ 326.8
Financial assets at FVTOCI, investments in equity and debt instruments	126,963.4	131,520.9
Financial assets at FVTOCI	129,918.7	134,776.8
Level 3 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	4,514.9	4,208.9	$ 3,910.7	$ 5,841.4
Measured at fair value on a recurring basis [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL		326.8
Financial assets at FVTOCI	129,918.7	134,776.8
Hedging derivative financial assets		25.9
Measured at fair value on a recurring basis [member] | Loans and receivables [member]
Disclosure of detailed information about financial instruments [line items]
Notes and accounts receivable, net	2,955.3	3,255.9
Measured at fair value on a recurring basis [member] | Level 1 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI	13,329.2	12,678.1
Hedging derivative financial assets		22.4
Measured at fair value on a recurring basis [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL		203
Financial assets at FVTOCI	112,074.6	118,013.6
Hedging derivative financial assets		3.5
Measured at fair value on a recurring basis [member] | Level 2 [member] | Loans and receivables [member]
Disclosure of detailed information about financial instruments [line items]
Notes and accounts receivable, net	2,955.3	3,255.9
Measured at fair value on a recurring basis [member] | Level 3 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL		123.8
Financial assets at FVTOCI	4,514.9	4,085.1
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL	2,259.4	162.1
Financial liabilities at FVTPL, Held for trading	94.1	982.3
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Cash flow hedges [member]
Disclosure of detailed information about financial instruments [line items]
Hedging derivative financial assets		3.5
Hedging derivative financial liabilities		1.8
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL	2,259.4	162.1
Financial liabilities at FVTPL, Held for trading	94.1	982.3
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Level 2 [member] | Cash flow hedges [member]
Disclosure of detailed information about financial instruments [line items]
Hedging derivative financial assets		3.5
Hedging derivative financial liabilities		1.8
Measured at fair value on a recurring basis [member] | Convertible Bonds [Member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL		123.8
Measured at fair value on a recurring basis [member] | Convertible Bonds [Member] | Level 3 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL		123.8
Measured at fair value on a recurring basis [member] | Corporate bonds [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	56,593.6	51,790
Measured at fair value on a recurring basis [member] | Corporate bonds [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	56,593.6	51,790
Measured at fair value on a recurring basis [member] | Agency bonds/Agency mortgage-backed securities [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	43,977.1	51,966.5
Measured at fair value on a recurring basis [member] | Agency bonds/Agency mortgage-backed securities [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	43,977.1	51,966.5
Measured at fair value on a recurring basis [member] | Asset-backed securities [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	8,368.3	10,815.9
Measured at fair value on a recurring basis [member] | Asset-backed securities [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	8,368.3	10,815.9
Measured at fair value on a recurring basis [member] | Government bonds [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	13,459.5	12,824.2
Measured at fair value on a recurring basis [member] | Government bonds [member] | Level 1 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	13,279.2	12,678.1
Measured at fair value on a recurring basis [member] | Government bonds [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, investments in equity and debt instruments	180.3	146.1
Measured at fair value on a recurring basis [member] | Publicly traded stocks [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, Investments in equity instruments	50
Measured at fair value on a recurring basis [member] | Publicly traded stocks [member] | Level 1 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, Investments in equity instruments	50
Measured at fair value on a recurring basis [member] | Futures Contract [member] | Fair value hedges [member]
Disclosure of detailed information about financial instruments [line items]
Hedging derivative financial assets	0.1	22.4
Hedging derivative financial liabilities	1.2
Measured at fair value on a recurring basis [member] | Futures Contract [member] | Level 1 [member] | Fair value hedges [member]
Disclosure of detailed information about financial instruments [line items]
Hedging derivative financial assets	0.1	22.4
Hedging derivative financial liabilities	1.2
Measured at fair value on a recurring basis [member] | Agency mortgage backed securities [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL		40.9
Measured at fair value on a recurring basis [member] | Agency mortgage backed securities [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTPL, mandatorily measured at FVTPL		40.9
Measured at fair value on a recurring basis [member] | Non-publicly traded stocks [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, Investments in equity instruments	4,514.9	4,124.3
Measured at fair value on a recurring basis [member] | Non-publicly traded stocks [member] | Level 2 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, Investments in equity instruments		39.2
Measured at fair value on a recurring basis [member] | Non-publicly traded stocks [member] | Level 3 [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets at FVTOCI, Investments in equity instruments	$ 4,514.9	$ 4,085.1

Financial Instruments - Summa_3

Financial Instruments - Summary of Level 3 Fair Value Were Equity Investments classified as Financial Assets at FVTOCI (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items]
Beginning balance	$ 131,520.9
Ending balance	126,963.4	$ 131,520.9
Level 3 [member]
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items]
Beginning balance	4,208.9	3,910.7	$ 5,841.4
Additions	175.2	372.3	212.5
Recognized in profit or loss	(3.8)
Recognized in other comprehensive income	409	129.5	(2,141.4)
Disposals and proceeds from return of capital of investments	(51.1)	(76.5)	(175.8)
Transfers out of level 3 (Note)		(43.6)
Effect of exchange rate changes	(223.3)	(83.5)	174
Ending balance	$ 4,514.9	$ 4,208.9	$ 3,910.7

Financial Instruments - Fair _2

Financial Instruments - Fair Value of Financial Instruments Not Measured at Fair Value but for which Fair Value is Disclosed (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Financial assets	$ 958,471.8	$ 747,870.1
Financial liabilities	748,224.6	534,565.8
Financial assets at amortised cost, class [member] | Corporate bonds [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets	10,970.2	7,648.8
Financial liabilities at amortised cost [member] | Bonds payable including long-term liabilities-current portion) [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	256,705.1	56,900
Not measured at fair value but for which the fair value is disclosed [member] | Level 2 [member] | Financial assets at amortised cost, class [member] | Corporate bonds [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets, at fair value	11,053.6	7,718.7
Not measured at fair value but for which the fair value is disclosed [member] | Level 2 [member] | Financial liabilities at amortised cost [member] | Bonds payable including long-term liabilities-current portion) [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value	$ 257,551.2	$ 57,739.1

Related Party Transactions - Su

Related Party Transactions - Summary of Significant Transactions between the Company and Other Related Parties (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)	Dec. 31, 2020USD ($)
Disclosure of transactions between related parties [line items]
Net revenue from sale of goods	$ 8,129.8	$ 6,253.9	$ 8,980.4
Receivables from related parties	558.1	862.1		$ 19.9
Payables to related parties	2,107.7	1,434.9
Other receivables from related parties	50.6	51.6		$ 1.8
Global Unichip Corporation [member]
Disclosure of transactions between related parties [line items]
Receivables from related parties	370.6	741.9
Xintec Inc. [member]
Disclosure of transactions between related parties [line items]
Receivables from related parties	187.5	120.2
Payables to related parties	1,358.6	736.9
Systems on Silicon Manufacturing Company Pte Ltd. [member]
Disclosure of transactions between related parties [line items]
Payables to related parties	400.8	487.9
Other receivables from related parties	45.3	46.5
Vanguard International Semiconductor Corporation [member]
Disclosure of transactions between related parties [line items]
Payables to related parties	311.4	154
Other receivables from related parties	4.3	3.9
Associates [member]
Disclosure of transactions between related parties [line items]
Net revenue from sale of goods	8,129.8	6,253.9	8,980.1
Net revenue from royalties	195.1	183.6	362.3
Purchases	7,606.4	6,301.4	8,809.5
Manufacturing expenses	5,440	2,823	2,974.6
Research and development expenses	256.5	163.4	83.1
Other related parties [member]
Disclosure of transactions between related parties [line items]
Net revenue from sale of goods			0.3
General and administrative expenses	120	120	$ 120.8
Other associates [member]
Disclosure of transactions between related parties [line items]
Payables to related parties	36.9	56.1
Other receivables from related parties	$ 1	$ 1.2

Related Party Transactions - Co

Related Party Transactions - Compensation to Directors and Other Key Management Personnel (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of transactions between related parties [abstract]
Short-term employee benefits	$ 2,666.7	$ 1,922.2	$ 2,004.9
Post-employment benefits	2.3	2.7	3.4
Compensation of key management personnel	$ 2,669	$ 1,924.9	$ 2,008.3

Pledged Assets - Additional Inf

Pledged Assets - Additional Information (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Certificates of deposit [member]
Disclosure of Pledged Assets [Line Items]
Financial assets pledged as collateral	$ 135.4	$ 114.5

Significant Contingent Liabil_2

Significant Contingent Liabilities and Unrecognized Commitments - Additional Information (Detail) - TWD ($) $ in Millions	Mar. 30, 1999	Dec. 31, 2020	Dec. 31, 2019
Letters of Credit [member]
Disclosure of contingent liabilities [line items]
Amounts available under unused letters of credit		$ 56.2	$ 60
Systems on Silicon Manufacturing Company Pte Ltd. [member]
Disclosure of contingent liabilities [line items]
Equity interest in joint venture	32.00%	39.00%
Minimum collective purchase capacity required		70.00%
Maximum purchase capacity required		28.00%
NXP B.V [member] | Systems on Silicon Manufacturing Company Pte Ltd. [member]
Disclosure of contingent liabilities [line items]
Equity interest in joint venture		61.00%
Technical Cooperation Agreement with Industrial Technology Research Institute [member]
Disclosure of contingent liabilities [line items]
Maximum capacity that can be used as per agreement		35.00%
Term of agreement		5 years
Renewal period of agreement		Automatically renewed for successive periods of five years unless otherwise terminated by either party with one year prior notice.
Notice period for contract termination		1 year

Significant Operation Losses -

Significant Operation Losses - Additional Information (Detail) - TWD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Sep. 30, 2018
Significant operation losses [line items]
Loss from virus outbreak		$ 2,596
Estimated loss from unqualified photoresist materials	$ 3,400

Operating Segments Informatio_2

Operating Segments Information - Geographic Information (Detail) - TWD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of geographical areas [line items]
Non-current Assets	$ 1,613,496.7	$ 1,392,005.7
Taiwan [member]
Disclosure of geographical areas [line items]
Non-current Assets	1,569,080.4	1,344,352.6
United States [member]
Disclosure of geographical areas [line items]
Non-current Assets	9,455.5	8,850.1
China [member]
Disclosure of geographical areas [line items]
Non-current Assets	34,456.4	38,586.6
Europe, the Middle East and Africa [member]
Disclosure of geographical areas [line items]
Non-current Assets	174.2	186.2
Japan [member]
Disclosure of geographical areas [line items]
Non-current Assets	327.2	27.1
Others [member]
Disclosure of geographical areas [line items]
Non-current Assets	$ 3	$ 3.1

Operating Segments Informatio_3

Operating Segments Information - Major Customers Representing at Least 10 Percent of Net Revenue (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020TWD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019TWD ($)	Dec. 31, 2018TWD ($)
Disclosure of major customers [line items]
NET REVENUE	$ 1,339,254.8	$ 47,694.3	$ 1,069,985.4	$ 1,031,473.6
Customer A [member]
Disclosure of major customers [line items]
NET REVENUE	$ 336,775.5		$ 247,213.3	$ 224,690.7
Percentage of entity's revenue	25.00%	25.00%	23.00%	22.00%
Customer B [member]
Disclosure of major customers [line items]
NET REVENUE	$ 167,390.8		$ 152,876.9	$ 83,885.6
Percentage of entity's revenue	12.00%	12.00%	14.00%	8.00%