Consolidated Statements of Changes in Shareholders' Equity (USD $) In Millions, except Share data in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balance, Value at Dec. 31, 2009	$ 16,241	$ 3,449	$ 5,620	$ 7,539	$ (417)	$ 50
Beginning balance, Shares at Dec. 31, 2009		689,750
Comprehensive income (loss):
Net income	637			608		29
Net change in other comprehensive income (loss)	82				82
Total comprehensive income (loss), After-Tax	719			608	82	29
Stock transactions:
In purchase acquisitions, Shares		57
In purchase acquisitions, Values	2	0	2
In connection with equity awards, net of repurchases, Shares		1,610
In connection with equity awards, net of repurchases, Values	31	8	23
In connection with dividend reinvestment plan, Shares		803
In connection with dividend reinvestment plan, Value	23	4	19
In connection with 401(k) plan, Shares		1,340
In connection with 401(k) plan, Value	38	7	31
Cash dividends declared on common stock	(312)			(312)
Equity-based compensation expense	58		58
Other, net	(13)			(2)		(11)
Ending balance, Value at Sep. 30, 2010	16,787	3,468	5,753	7,833	(335)	68
Ending balance, Shares at Sep. 30, 2010		693,560
Beginning balance, Value at Dec. 31, 2010	16,498	3,472	5,776	7,935	(747)	62
Beginning balance, Shares at Dec. 31, 2010		694,381
Comprehensive income (loss):
Net income	932			898		34
Net change in other comprehensive income (loss)	391				391
Total comprehensive income (loss), After-Tax	1,323			898	391	34
Stock transactions:
In purchase acquisitions, Shares		26
In purchase acquisitions, Values	1	0	1
In connection with equity awards, Shares		1,918
In connection with equity awards, Values	1	10	(9)
Shares repurchased in connection with equity awards, Shares		(642)
Shares repurchased in connection with equity awards, Value	(18)	(3)	(15)
In connection with dividend reinvestment plan, Shares		580
In connection with dividend reinvestment plan, Value	16	3	13
In connection with 401(k) plan, Shares		838
In connection with 401(k) plan, Value	23	4	19
Cash dividends declared on common stock	(341)			(341)
Equity-based compensation expense	73		73
Other, net	(35)		(2)	1		(34)
Ending balance, Value at Sep. 30, 2011	$ 17,541	$ 3,486	$ 5,856	$ 8,493	$ (356)	$ 62
Ending balance, Shares at Sep. 30, 2011		697,101