Consolidated Statements Of Shareholders' Equity (USD $) In Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Deferred Compensation, Share-based Payments [Member]	Accumulated Net Unrealized Investment Gain (Loss) [Member]	Accumulated Translation Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Shares Issued To Employee Trust [Member]
Cumulative effect of adjustment resulting from adoption of new accounting guidance at Dec. 31, 2010					$ (139)
Balance - beginning of period at Dec. 31, 2010		10,161	(330)	5,623	5,926	2	1,399	262	(67)		(2)
Change in period, net of income tax expense of $(234) and $(112)							127
Change in period, net of income tax benefit (expense) of $(44) and $(30)								119
Change in period, net of income tax benefit of $2 and $1									(1)
Dividends declared on Common Shares-par value reduction		113
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			80
Net shares redeemed under employee share-based compensation plans				(111)
Exercise of stock options		47		26
Share-based compensation expense and other				103
Funding of dividends declared from Additional paid-in capital				236	(236)
Net income (loss)	805				805
Dividends declared on Common Shares					(236)
Balance - end of period at Sep. 30, 2011	23,581	10,095	(350)	5,405	6,592	2	1,526	381	(68)	1,839	(2)
Cumulative effect of adjustment resulting from adoption of new accounting guidance at Jun. 30, 2011
Common Shares repurchased			(100)
Net income (loss)	(39)
Balance - end of period at Sep. 30, 2011	23,581		(350)			2				1,839	(2)
Balance - beginning of period at Dec. 31, 2011	24,332	10,095	(327)	5,326	7,327		1,715	258	(62)
Change in period, net of income tax expense of $(234) and $(112)							988
Change in period, net of income tax benefit (expense) of $(44) and $(30)								118
Change in period, net of income tax benefit of $2 and $1									(3)
Dividends declared on Common Shares-par value reduction		336
Common Shares repurchased			(7)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			147
Net shares redeemed under employee share-based compensation plans				(102)
Exercise of stock options				(8)
Share-based compensation expense and other				93
Funding of dividends declared from Additional paid-in capital				200	(200)
Net income (loss)	1,941				1,941
Dividends declared on Common Shares					(200)
Balance - end of period at Sep. 30, 2012	$ 26,963	$ 9,759	$ (187)	$ 5,109	$ 9,268		$ 2,703	$ 376	$ (65)	$ 3,014