Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions		Total	Cumulative effect, period of adoption, adjustment	Cumulative effect, period of adoption, adjusted balance	Common stock	Common stock Cumulative effect, period of adoption, adjustment	Common stock Cumulative effect, period of adoption, adjusted balance	Additional paid-in capital	Additional paid-in capital Cumulative effect, period of adoption, adjustment	Additional paid-in capital Cumulative effect, period of adoption, adjusted balance	Retained earnings	Retained earnings Cumulative effect, period of adoption, adjustment	Retained earnings Cumulative effect, period of adoption, adjusted balance	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Cumulative effect, period of adoption, adjustment	Accumulated other comprehensive income (loss) Cumulative effect, period of adoption, adjusted balance	Treasury stock	Treasury stock Cumulative effect, period of adoption, adjustment	Treasury stock Cumulative effect, period of adoption, adjusted balance
Balance, beginning of period at Dec. 31, 2017		$ 24,598		$ 24,598	$ 135		$ 135	$ 2,052		$ 2,052	$ 29,895		$ 29,669	$ 4,028		$ 4,254	$ (11,512)		$ (11,512)
Balance, beginning of period (Accounting Standards Update 2016-01) at Dec. 31, 2017	[1]		$ 0			$ 0			$ 0			$ 148			$ (148)			$ 0
Balance, beginning of period (Accounting Standards Update 2018-02) at Dec. 31, 2017	[1]		0			0			0			(374)			374			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		2,920			0			0			2,920			0			0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		228			0			0			0			228			0
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments		(2,316)			0			0			0			(2,316)			0
Unrealized gains (losses) on derivatives during period, net of income taxes		2			0			0			0			2			0
Pension liability adjustment during period, net of income taxes		(17)			0			0			0			(17)			0
Dividends to shareholders		(801)			0			0			(801)			0			0
Exercise of stock options		34			0			34			0			0			0
Share-based compensation		54			0			54			0			0			0
Purchases of treasury stock		(1,317)			0			0			0			0			(1,317)
Treasury stock reissued		77			0			37			0			0			40
Balance, end of period at Dec. 31, 2018		23,462			135			2,177			31,788			2,151			(12,789)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		3,304			0			0			3,304			0			0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		224			0			0			0			224			0
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments		4,314			0			0			0			4,314			0
Unrealized gains (losses) on derivatives during period, net of income taxes		(9)			0			0			0			(9)			0
Pension liability adjustment during period, net of income taxes		(65)			0			0			0			(65)			0
Dividends to shareholders		(801)			0			0			(801)			0			0
Exercise of stock options		29			0			29			0			0			0
Share-based compensation		54			0			54			0			0			0
Purchases of treasury stock		(1,656)			0			0			0			0			(1,656)
Treasury stock reissued		103			0			53			0			0			50
Balance, end of period at Dec. 31, 2019		28,959		$ 29,751	135		$ 135	2,313		$ 2,313	34,291		$ 34,235	6,615		$ 7,463	(14,395)		$ (14,395)
Balance, end of period (Accounting Standards Update 2016-13) at Dec. 31, 2019	[2]		(56)			0			0			(56)			0			0
Balance, end of period (Accounting Standards Update 2019-04) at Dec. 31, 2019	[2]		$ 848			$ 0			$ 0			$ 0			$ 848			$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		4,778			0			0			4,778			0			0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		514			0			0			0			514			0
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments		965			0			0			0			965			0
Unrealized gains (losses) on derivatives during period, net of income taxes		(1)			0			0			0			(1)			0
Pension liability adjustment during period, net of income taxes		(7)			0			0			0			(7)			0
Dividends to shareholders		(1,029)			0			0			(1,029)			0			0
Exercise of stock options		12			0			12			0			0			0
Share-based compensation		53			0			53			0			0			0
Purchases of treasury stock		(1,565)			0			0			0			0			(1,565)
Treasury stock reissued		88			0			32			0			0			56
Balance, end of period at Dec. 31, 2020		$ 33,559			$ 135			$ 2,410			$ 37,984			$ 8,934			$ (15,904)

[1] See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2018.

[2] See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2020.