Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions		Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Cumulative effect, period of adoption, adjustment	Cumulative effect, period of adoption, adjustment Common stock	Cumulative effect, period of adoption, adjustment Additional paid-in capital	Cumulative effect, period of adoption, adjustment Retained earnings	Cumulative effect, period of adoption, adjustment Accumulated other comprehensive income (loss)	Cumulative effect, period of adoption, adjustment Treasury stock	Cumulative effect, period of adoption, adjusted balance	Cumulative effect, period of adoption, adjusted balance Common stock	Cumulative effect, period of adoption, adjusted balance Additional paid-in capital	Cumulative effect, period of adoption, adjusted balance Retained earnings	Cumulative effect, period of adoption, adjusted balance Accumulated other comprehensive income (loss)	Cumulative effect, period of adoption, adjusted balance Treasury stock
Balance, beginning of period at Dec. 31, 2019		$ 28,959	$ 135	$ 2,313	$ 34,291	$ 6,615	$ (14,395)							$ 29,751	$ 135	$ 2,313	$ 34,235	$ 7,463	$ (14,395)
Balance, beginning of period (Accounting Standards Update 2016-13) at Dec. 31, 2019	[1]							$ (56)	$ 0	$ 0	$ (56)	$ 0	$ 0
Balance, beginning of period (Accounting Standards Update 2019-04) at Dec. 31, 2019	[1]							$ 848	$ 0	$ 0	$ 0	$ 848	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		566	0	0	566	0	0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		80	0	0	0	80	0
Unrealized gains (losses) on fixed maturity securities during period, net of income taxes and reclassification adjustments		(3,353)	0	0	0	(3,353)	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		0	0	0	0	0	0
Dividends to shareholders		(202)	0	0	(202)	0	0
Exercise of stock options		5	0	5	0	0	0
Share-based compensation		7	0	7	0	0	0
Purchases of treasury stock		(476)	0	0	0	0	(476)
Treasury stock reissued		26	0	9	0	0	17
Balance, end of period at Mar. 31, 2020		26,402	135	2,334	34,599	4,188	(14,854)
Balance, beginning of period at Dec. 31, 2020		33,559	135	2,410	37,984	8,934	(15,904)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		1,293	0	0	1,293	0	0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		(565)	0	0	0	(565)	0
Unrealized gains (losses) on fixed maturity securities during period, net of income taxes and reclassification adjustments		(1,567)	0	0	0	(1,567)	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		4	0	0	0	4	0
Dividends to shareholders		0	0	0	0	0	0
Exercise of stock options		9	0	9	0	0	0
Share-based compensation		9	0	9	0	0	0
Purchases of treasury stock		(668)	0	0	0	0	(668)
Treasury stock reissued		28	0	10	0	0	18
Balance, end of period at Mar. 31, 2021		$ 32,103	$ 135	$ 2,438	$ 39,277	$ 6,807	$ (16,554)

[1] See Note 1 of the Notes to the Consolidated Financial Statements in the Company's 2020 Annual Report on Form 10-K.See the accompanying Notes to the Consolidated Financial Statements.