Premises and Equipment (Summary of Premises and Equipment) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Premises and Equipment, Gross
Land and land improvements	$ 508	$ 495
Buildings and building improvements	1,220	1,180
Furniture and equipment	1,132	1,117
Leasehold improvements	521	499
Construction in progress	37	22
Capitalized leases on premises and equipment	52	41
Total	3,470	3,354
Less-accumulated depreciation and amortization	(1,615)	(1,514)
Net premises and equipment	$ 1,855	$ 1,840