Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions		Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Balance, beginning 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		928	0	0	928	0	0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		(1)	0	0	0	(1)	0
Unrealized gains (losses) on fixed maturity securities during period, net of income taxes and reclassification adjustments		2,327	0	0	0	2,327	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		6	0	0	0	6	0
Dividends to shareholders		(203)	0	0	(203)	0	0
Exercise of stock options		11	0	11	0	0	0
Share-based compensation		8	0	8	0	0	0
Purchases of treasury stock		(517)	0	0	0	0	(517)
Treasury stock reissued		30	0	12	0	0	18
Balance, end of period at Mar. 31, 2019		26,049	135	2,208	32,513	4,481	(13,288)
Balance, beginning of period at Dec. 31, 2019		28,959	135	2,313	34,291	6,615	(14,395)
Cumulative effect of change in accounting principle, net of income taxes (Accounting Standards Update 2016-13) at Dec. 31, 2019	[1]	(56)	0	0	(56)	0	0
Cumulative effect of change in accounting principle, net of income taxes (Accounting Standards Update 2019-04) at Dec. 31, 2019	[1]	848	0	0	0	848	0
Adjusted balance, beginning of period at Dec. 31, 2019		29,751	135	2,313	34,235	7,463	(14,395)
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)

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