Accumulated Other Comprehensive Income (Loss) (Balances in Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Total	$ (713)		$ (747)
Pre-tax [Member]
Unrecognized net pension and postretirement costs	(965)		(587)
Unrealized net gains (losses) on cash flow hedges	(254)		(75)
Unrealized net gains (losses) on securities available for sale	421		(250)
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(311)	[1]	(281)	[1]
Other comprehensive income, other, net	(37)		(6)
Total	(1,146)		(1,199)
Deferred tax expense [Member]
Unrecognized net pension and postretirement costs	(362)		(219)
Unrealized net gains (losses) on cash flow hedges	(95)		(28)
Unrealized net gains (losses) on securities available for sale	158		(93)
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(116)	[1]	(105)	[1]
Other comprehensive income, other, net	(18)		(7)
Total	(433)		(452)
Accumulated other comprehensive income (loss) [Member]
Unrecognized net pension and postretirement costs	(603)		(368)
Unrealized net gains (losses) on cash flow hedges	(159)		(47)
Unrealized net gains (losses) on securities available for sale	263		(157)
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(195)	[1]	(176)	[1]
Other comprehensive income, other, net	(19)		1
Total	$ (713)		$ (747)

[1] Certain securities available for sale are covered by loss sharing agreements with the FDIC. Refer to the Securities footnote to these financial statements for additional information.