Consolidated Statements Of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Common shares in treasury [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]	Cumulative Foreign Currency Translation Adjustment [Member]	Postretirement Benefit Liability Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance					$ 23,613	$ 1,058
Balance - beginning of period at Dec. 31, 2016		$ 11,121	$ (1,480)	$ 15,335	23,613	1,058	$ (1,663)	$ 291
Common Shares repurchased			(140)
Net shares redeemed under employee share-based compensation plans			222	(260)
Exercise of stock options				(21)
Share-based compensation expense				65
Net income	$ 1,093				1,093
Funding of dividends declared to Retained earnings				(324)
Funding of dividends declared from Additional paid-in capital					324
Dividends declared on Common Shares					(324)
Change in period, before reclassification from AOCI, net of income tax benefit (expense) of $226 and $(102)						205
Amounts reclassified from AOCI, net of income tax expense of $(3) and $(6)						2
Change in period, net of income tax benefit (expense) of $223 and $(108)						207
Change in period, net of income tax expense of $(19) and $(3)							131
Change in period, net of income tax benefit (expense) of $4 and $(4)								(24)
Balance - end of period at Mar. 31, 2017	49,224	11,121	(1,398)	14,795	24,706	1,265	(1,532)	267	$ 0
Balance - beginning of period at Dec. 31, 2017	51,172	11,121	(1,944)	13,978	27,474	1,450	(1,187)	280
Common Shares repurchased			0
Net shares redeemed under employee share-based compensation plans			217	(262)
Exercise of stock options				(16)
Share-based compensation expense				62
Net income	1,082				1,082
Funding of dividends declared to Retained earnings				(332)
Funding of dividends declared from Additional paid-in capital					332
Dividends declared on Common Shares					(332)
Change in period, before reclassification from AOCI, net of income tax benefit (expense) of $226 and $(102)						(1,008)
Amounts reclassified from AOCI, net of income tax expense of $(3) and $(6)						20
Change in period, net of income tax benefit (expense) of $223 and $(108)						(988)
Change in period, net of income tax expense of $(19) and $(3)							378
Change in period, net of income tax benefit (expense) of $4 and $(4)								(19)
Balance - end of period at Mar. 31, 2018	$ 51,287	$ 11,121	$ (1,727)	$ 13,430	$ 28,965	$ 46	$ (809)	$ 261	$ (502)