Acquisition (Assets And Liabilities At Estimated Fair Value On Acquisition Date) (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Jul. 31, 2011	Jul. 28, 2011
Fair value of consideration paid		$ 803
Premises and equipment		34
Core deposit intangible		34
Accrued income and other assets		304
Total identifiable assets acquired		4,678
Accrued expenses and other liabilities		47
Total liabilities assumed		4,360
Fair value of net identifiable assets acquired		318
Goodwill resulting from acquisition		485
Common stock, issued shares	24,283,711
Common Stock Issued [Member]
Fair value of consideration paid		793
Warrants Issued [Member]
Fair value of consideration paid		7
Stock Options Issued [Member]
Fair value of consideration paid		3
Cash And Cash Equivalents [Member]
Fair value of identifiable assets acquired		721
Investment Securities Available-For-Sale [Member]
Fair value of identifiable assets acquired		1,492
Total Loans [Member]
Fair value of identifiable assets acquired		2,093
Deposits [Member]
Fair value of liabilities assumed		4,029
Short-Term Borrowings [Member]
Fair value of liabilities assumed		22
Medium- And Long-Term Debt [Member]
Fair value of liabilities assumed		$ 262