Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data	Jun. 30, 2011	Dec. 31, 2010
Assets
Interest bearing deposits in banks	$ 2,477	$ 217
Fair Value of Securities held to maturity	1,610	1,560
Other asset	3,646	3,499
Liabilities
Long-term debt	7,069	5,598
Other liabilities	1,338	1,024
UNBC Stockholder's Equity:
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock:
Common Stock, Shares Authorized	300,000,000	300,000,000
Common Stock, Par or Stated Value Per Share	$ 1	$ 1
Common Stock, Shares, Issued	136,330,829	136,330,829
Variable Interest Entity, Not Primary Beneficiary [Member]
Assets
Interest bearing deposits in banks	24	11
Other asset	272	283
Liabilities
Long-term debt	8	8
Other liabilities	$ 2	$ 2