Consolidated Statement of Changes in Shareholders' Equity (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Convertible preferred stock - savings plan
Convertible preferred stock - savings plan, balance, beginning of year				$ 68
Convertible preferred stock - savings plan, redemptions during period				(5)
Convertible preferred stock - savings plan, conversion to common stock				(63)
Common stock
Common stock, balance, beginning of year			20,732	20,162
Common stock, employee share-based compensation			219	286
Common stock, common shares issued - conversion of preferred stock				93
Common stock, compensation amortization under share-based plans and other changes			134	123
Common stock, balance, end of period	21,085	20,664	21,085	20,664
Retained earnings
Retained earnings, balance, beginning of year			19,579	18,847
Net income	864	333	2,169	808
Dividends			(522)	(503)
Premium on preferred stock converted to common stock				(30)
Retained earnings, other				5
Retained earnings, balance, end of period	21,226	19,127	21,226	19,127
Accumulated other comprehensive income, net of tax
Accumulated other comprehensive income, net of tax, balance, beginning of year			2,005	1,255
Other comprehensive income	406	321	531	777
Accumulated other comprehensive income, net of tax, balance, end of period	2,536	2,032	2,536	2,032
Treasury stock (at cost)
Treasury stock (at cost), balance, beginning of year			(17,839)	(14,857)
Treasury stock (at cost), treasury shares acquired - share repurchase authorization	(350)		(1,050)	(1,712)
Treasury stock (at cost), net shares acquired related to employee share-based compensation plans			(53)	(82)
Treasury stock (at cost), balance, end of period	(18,942)	(16,651)	(18,942)	(16,651)
Total common shareholders' equity	25,905	25,172	25,905	25,172
Total shareholders' equity	$ 25,905	$ 25,172	$ 25,905	$ 25,172
Common shares outstanding
Common shares outstanding, balance, beginning of year			392.8	434.6
Common shares outstanding, treasury shares acquired - share repurchase authorization	(5.4)		(17.0)	(30.1)
Common shares outstanding, net shares issued under employee share-based compensation plans			6.2	6.8
Common shares outstanding, common shares issued - conversion of preferred stock				1.5
Common shares outstanding, balance, end of period	382.0	412.8	382.0	412.8