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, 2011		$ 10,095	$ (327)	$ 5,326	$ 7,327	$ 1,715	$ 258	$ (62)
Dividends declared on Common Shares-par value reduction		0
Common Shares repurchased			(7)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			107
Net shares redeemed under employee share-based compensation plans				(95)
Exercise of stock options				(10)
Share-based compensation expense and other				33
Funding of dividends declared from Additional paid-in capital				200	(200)
Net income	973				973
Dividends declared on Common Shares					(200)
Change in period, net of income tax benefit (expense) of $56 and $(49)						243
Change in period, net of income tax benefit (expense) of $55 and $(32)							56
Change in period, net of income tax benefit (expense) of $(8) and $1								(1)
Balance - end of period at Mar. 31, 2012	25,431	10,095	(227)	5,054	8,300	1,958	314	(63)	2,209
Balance - beginning of period at Dec. 31, 2012	27,531	9,591	(159)	5,179	10,033	2,633	339	(85)
Dividends declared on Common Shares-par value reduction		(168)
Common Shares repurchased			(154)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			101
Net shares redeemed under employee share-based compensation plans				(114)
Exercise of stock options				(12)
Share-based compensation expense and other				42
Funding of dividends declared from Additional paid-in capital				0	0
Net income	953				953
Dividends declared on Common Shares					0
Change in period, before reclassification from AOCI, net of income tax benefit of $51						(65)
Amounts reclassified from AOCI, net of income tax expense of $5						(30)
Change in period, net of income tax benefit (expense) of $56 and $(49)						(95)
Change in period, net of income tax benefit (expense) of $55 and $(32)							(156)
Change in period, net of income tax benefit (expense) of $(8) and $1								14
Balance - end of period at Mar. 31, 2013	$ 27,942	$ 9,423	$ (212)	$ 5,095	$ 10,986	$ 2,538	$ 183	$ (71)	$ 2,650