Accumulated Other Comprehensive Income (Loss) (Balances in Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Total	$ (559)	$ (713)
Pre-tax [Member]
Unrecognized net pension and postretirement costs	(1,146)	(965)
Unrealized net gains (losses) on cash flow hedges	(277)	(254)
Unrealized net gains (losses) on securities available for sale	960	421
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(410)	(311)
Other, net	(30)	(37)
Total	(903)	(1,146)
Deferred tax expense (benefit) [Member]
Unrecognized net pension and postretirement costs	(432)	(362)
Unrealized net gains (losses) on cash flow hedges	(104)	(95)
Unrealized net gains (losses) on securities available for sale	362	158
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(154)	(116)
Other, net	(16)	(18)
Total	(344)	(433)
AOCI [Member]
Unrecognized net pension and postretirement costs	(714)	(603)
Unrealized net gains (losses) on cash flow hedges	(173)	(159)
Unrealized net gains (losses) on securities available for sale	598	263
FDIC's share of unrealized (gains) losses on securities available for sale under the loss share agreements	(256)	(195)
Other, net	(14)	(19)
Total	$ (559)	$ (713)