Consolidated Statements Of Shareholders' Equity (USD $) In Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Unrealized Investment Gain (Loss) [Member]	Accumulated Translation Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance - beginning of period at Dec. 31, 2013		$ 8,899	$ (255)	$ 5,238	$ 13,791	$ 1,174	$ 63	$ (85)
Dividends declared on Common Shares – par value reduction		(175)
Net shares redeemed under employee share-based compensation plans			144	(154)
Common Shares repurchased			(332)
Exercise of stock options				(18)
Share-based compensation expense and other				52
Funding of dividends declared to Retained earnings				(81)
Net income	734				734
Funding of dividends declared from Additional paid-in capital					81
Dividends declared on Common Shares					(81)
Change in period, before reclassification from AOCI, net of income tax expense of $(87) and $(90)						429
Amounts reclassified from AOCI, net of income tax benefit (expense) of $4 and $(3)						(9)
Change in period, net of income tax expense of $(83) and $(93)						420
Change in period, net of income tax benefit (expense) of $11 and $(8)							(41)
Change in period, net of income tax benefit (expense) of $(3) and $3								(5)
Balance - end of period at Mar. 31, 2014	29,369	8,724	(443)	5,037	14,525	1,594	22	(90)	1,526
Balance - beginning of period at Dec. 31, 2014	29,587	8,055	(1,448)	5,145	16,644	1,851	(581)	(79)
Dividends declared on Common Shares – par value reduction		(222)
Net shares redeemed under employee share-based compensation plans			143	(153)
Common Shares repurchased			(340)
Exercise of stock options				(18)
Share-based compensation expense and other				63
Funding of dividends declared to Retained earnings				0
Net income	681				681
Funding of dividends declared from Additional paid-in capital					0
Dividends declared on Common Shares					0
Change in period, before reclassification from AOCI, net of income tax expense of $(87) and $(90)						354
Amounts reclassified from AOCI, net of income tax benefit (expense) of $4 and $(3)						7
Change in period, net of income tax expense of $(83) and $(93)						361
Change in period, net of income tax benefit (expense) of $11 and $(8)							(410)
Change in period, net of income tax benefit (expense) of $(3) and $3								10
Balance - end of period at Mar. 31, 2015	$ 29,702	$ 7,833	$ (1,645)	$ 5,037	$ 17,325	$ 2,212	$ (991)	$ (69)	$ 1,152