Earnings Per Common Share (EPS) (Details) (USD $) In Millions, except Per Share data	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Basic and diluted:
Income from continuing operations	$ 1,295		$ 1,017		$ 2,472		$ 1,902
Earnings allocated to participating share awards and other items	(15)		(13)		(30)		(25)
Income from discontinued operations, net of tax	36		0		36		0
Net income attributable to common shareholders	1,316		1,004		2,478		1,877
Average common shares outstanding for earnings per common share:
Basic: Weighted-average common stock	1,190		1,190		1,190		1,188
Add: weighted-average stock options and warrants	7		7		7		6
Diluted	1,197		1,197		1,197		1,194
Basic EPS:
Income from continuing operations attributable to common shareholders	$ 1.08	[1]	$ 0.84	[1]	$ 2.05	[2]	$ 1.58	[2]
Income from discontinued operations, net of tax	$ 0.03	[1]	$ 0	[1]	$ 0.03	[2]	$ 0	[2]
Net income attributable to common shareholders	$ 1.11	[1]	$ 0.84	[1]	$ 2.08	[2]	$ 1.58	[2]
Diluted EPS:
Income from continuing operations attributable to common shareholders	$ 1.07	[1]	$ 0.84	[1]	$ 2.04	[2]	$ 1.57	[2]
Income from discontinued operations, net of tax	$ 0.03	[1]	$ 0	[1]	$ 0.03	[2]	$ 0	[2]
Net income attributable to common shareholders	$ 1.10	[1]	$ 0.84	[1]	$ 2.07	[2]	$ 1.57	[2]
Earnings Per Common Share (Textuals) [Abstract]
Subordinated debentures	$ 750		$ 750		$ 750		$ 750
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per Share, amount	19		35		20		38

[1] Represents income from continuing operations or net income, as applicable, less earnings allocated to participating share awards and other items of $15 million and $13 million for the three months ended June 30, 2011 and 2010, respectively.

[2] Represents income from continuing operations or net income, as applicable, less earnings allocated to participating share awards and other items of $30 million and $25 million for the six months ended June 30, 2011 and 2010, respectively.