Goodwill and Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Jul. 31, 2011	Dec. 31, 2011 segments	Jul. 28, 2011
Business acquisition date	July 28, 2011
Goodwill attributable to Sterling acquisition			$ 485
Number of Major Business Segments		3
Core deposit intangible			34
Core Deposits [Member]
Core deposit intangible			34
Core deposit intangible amortization period (in years)		10
Acquired intangible asset		29
Amortization expense on acquired intangible asset		5