CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement of Other Comprehensive Income [Abstract]
Net income	$ 183	$ 235
Net change in unrealized gains (losses), net of tax as applicable on:
Securities available-for-sale, not other-than-temporarily impaired	(150)	(127)
Derivatives designated as cash flow hedges	23	37
Unrecognized actuarial gains, transition obligation and prior service costs relating to pension and postretirement benefits, net of tax	0	1
Other comprehensive income, net of tax	(127)	(89)
Comprehensive income	$ 56	$ 146