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, 2012		$ 9,591	$ (159)	$ 5,179	$ 10,033	$ 2,633	$ 339	$ (85)
Dividends declared on Common Shares – par value reduction		(168)
Common Shares repurchased			(154)
Net shares redeemed under employee share-based compensation plans			101	(114)
Exercise of stock options				(12)
Share-based compensation expense and other				42
Funding of dividends declared to Retained earnings				0
Net income	953				953
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) benefit of $(90) and $51						(65)
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(3) and $5						(30)
Change in period, net of income tax (expense) benefit of $(93) and $56						(95)
Change in period, net of income tax (expense) benefit of $(8) and $55							(156)
Change in period, net of income tax (expense) benefit of $3 and $(8)								14
Balance - end of period at Mar. 31, 2013	27,942	9,423	(212)	5,095	10,986	2,538	183	(71)	2,650
Balance - beginning of period at Dec. 31, 2013	28,825	8,899	(255)	5,238	13,791	1,174	63	(85)
Dividends declared on Common Shares – par value reduction		(175)
Common Shares repurchased			(332)
Net shares redeemed under employee share-based compensation plans			144	(154)
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) benefit of $(90) and $51						429
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(3) and $5						(9)
Change in period, net of income tax (expense) benefit of $(93) and $56						420
Change in period, net of income tax (expense) benefit of $(8) and $55							(41)
Change in period, net of income tax (expense) benefit of $3 and $(8)								(5)
Balance - end of period at Mar. 31, 2014	$ 29,369	$ 8,724	$ (443)	$ 5,037	$ 14,525	$ 1,594	$ 22	$ (90)	$ 1,526