Fair Value Measurements (Details 4) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
ASSETS
Trading account assets	$ 623,000,000	$ 985,000,000
Securities available for sale	16,012,000,000	21,933,000,000
Held-to-maturity securities	2,109,000,000	17,000,000
Other investments	1,163,000,000	1,358,000,000
Loans, net of allowance	48,571,000,000	48,503,000,000
Loans held for sale	728,000,000	467,000,000	443,000,000
Derivative assets	945,000,000	1,006,000,000
LIABILITIES
Long-term debt	9,520,000,000	10,592,000,000
Derivative liabilities	1,026,000,000	1,142,000,000
Segment, Discontinued Operations [Member]
ASSETS
Loans, net of allowance	5,708,000,000	6,337,000,000
Loans held for sale	0	15,000,000
Segment, Discontinued Operations [Member] | Education Lending [Member]
ASSETS
Loans, net of allowance	5,708,000,000	6,337,000,000
Loans held for sale	0	15,000,000
Fair Value By Balance Sheet Grouping (Textual)
Loans in Portfolio	76,000,000
Residential Real Estate Mortgage Loans [Member]
ASSETS
Loans, net of allowance	1,900,000,000	1,800,000,000
Carrying Amount [Member]
ASSETS
Cash and short-term investments	4,213,000,000	1,622,000,000
Trading account assets	623,000,000	985,000,000
Securities available for sale	16,012,000,000	21,933,000,000
Held-to-maturity securities	2,109,000,000	17,000,000
Other investments	1,163,000,000	1,358,000,000
Loans, net of allowance	48,571,000,000	48,503,000,000
Loans held for sale	728,000,000	467,000,000
Mortgage servicing assets	173,000,000	196,000,000
Derivative assets	945,000,000	1,006,000,000
LIABILITIES
Deposits with no stated maturity	51,014,000,000	45,598,000,000
Time deposits	10,942,000,000	15,012,000,000
Short-term borrowings	2,048,000,000	3,196,000,000
Long-term debt	9,520,000,000	10,592,000,000
Derivative liabilities	1,026,000,000	1,142,000,000
Carrying Amount [Member] | Segment, Discontinued Operations [Member] | Education Lending [Member]
ASSETS
Loans, net of allowance	2,900,000,000	3,200,000,000
Loans held for sale	0	15,000,000
Fair Value [Member]
ASSETS
Cash and short-term investments	4,213,000,000	1,622,000,000
Trading account assets	623,000,000	985,000,000
Securities available for sale	16,012,000,000	21,933,000,000
Held-to-maturity securities	2,133,000,000	17,000,000
Other investments	1,163,000,000	1,358,000,000
Loans, net of allowance	47,561,000,000	46,140,000,000
Loans held for sale	728,000,000	467,000,000
Mortgage servicing assets	245,000,000	284,000,000
Derivative assets	945,000,000	1,006,000,000
LIABILITIES
Deposits with no stated maturity	51,014,000,000	45,598,000,000
Time deposits	11,253,000,000	15,502,000,000
Short-term borrowings	2,048,000,000	3,196,000,000
Long-term debt	9,792,000,000	10,611,000,000
Derivative liabilities	1,026,000,000	1,142,000,000
Fair Value [Member] | Segment, Discontinued Operations [Member] | Education Lending [Member]
ASSETS
Loans, net of allowance	2,500,000,000	2,800,000,000
Fair Value By Balance Sheet Grouping (Textual)
Loans in the trusts	2,700,000,000	3,100,000,000
Securities issued by the education lending securitization trust	$ 2,500,000,000	$ 3,000,000,000