Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net Income Attributable to UNBC	$ 141	$ 187	$ 288	$ 382
Other Comprehensive Income (Loss), Net of Tax:
Net change in unrealized gains (losses) on cash flow hedges	(3)	15	(3)	20
Net change in unrealized gains (losses) on investment securities	(330)	47	(394)	86
Foreign currency translation adjustment	(2)	(1)	(3)
Net change in gains (losses) on pension and other postretirement benefits	17	14	35	30
Total other comprehensive income (loss)	(318)	75	(365)	136
Comprehensive Income (Loss) Attributable to UNBC	(177)	262	(77)	518
Comprehensive loss from noncontrolling interests	(3)	(5)	(7)	(9)
Total Comprehensive Income (Loss)	$ (180)	$ 257	$ (84)	$ 509

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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