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, 2015			$ 135	$ 1,760	$ 24,007	$ 625	$ (8,819)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options				46
Share-based compensation				64
Treasury stock reissued				38			69
Net earnings		$ 2,659			2,659
Dividends to shareholders ($1.04 per share in 2018, $.87 per share in 2017 and $.83 per share in 2016)					(685)
Unrealized foreign currency translation gains (losses) during period, net of income taxes						213
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments	[1]					1,819
Unrealized gains (losses) on derivatives during period, net of income taxes						2
Pension liability adjustment during period, net of income taxes						(29)
Purchases of treasury stock							(1,422)
Balance, end of period at Dec. 31, 2016		20,482	135	1,908	25,981	2,630	(10,172)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2016-01	[1]				0	0
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2018-02	[1]				0	0
Exercise of stock options				38
Share-based compensation				51
Treasury stock reissued				55			51
Net earnings		4,604			4,604
Dividends to shareholders ($1.04 per share in 2018, $.87 per share in 2017 and $.83 per share in 2016)					(690)
Unrealized foreign currency translation gains (losses) during period, net of income taxes						233
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments	[1]					1,159
Unrealized gains (losses) on derivatives during period, net of income taxes						1
Pension liability adjustment during period, net of income taxes						5
Purchases of treasury stock							(1,391)
Balance, end of period at Dec. 31, 2017		24,598	135	2,052	29,895	4,028	(11,512)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2016-01	[1]				0	0
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2018-02	[1]				0	0
Exercise of stock options				34
Share-based compensation				54
Treasury stock reissued				37			40
Net earnings		2,920			2,920
Dividends to shareholders ($1.04 per share in 2018, $.87 per share in 2017 and $.83 per share in 2016)					(801)
Unrealized foreign currency translation gains (losses) during period, net of income taxes						228
Unrealized gains (losses) on fixed maturity securities during the period, net of income taxes and reclassification adjustments	[1]					(2,316)
Unrealized gains (losses) on derivatives during period, net of income taxes						2
Pension liability adjustment during period, net of income taxes						(17)
Purchases of treasury stock							(1,317)
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]
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2016-01	[1]				148	(148)
Cumulative effect of change in accounting principle, net of income taxes | Accounting Standards Update 2018-02	[1]				$ (374)	$ 374

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