CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net income	$ 430	$ 265
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Unrealized holding gains (losses) on available-for-sale securities arising during period	7	(37)
Reclassification adjustment for net gains included in net income	(5)	(7)
Unrealized holding gains on cash flow hedge derivatives arising during period	6
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	(13)	(9)
Net actuarial loss	3	2
Other comprehensive loss	(2)	(51)
Comprehensive income attributable to Bancorp	$ 428	$ 214