Loans - Consumer, Excluding Credit Card Loans, Impaired Loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consumer, excluding credit card | Days Past Due, 30 or More
Impaired loans:
Period past due, credit analysis factors, charge off criteria	30 days
Consumer, excluding credit card | Days Past Due, 30 or More
Impaired loans:
Period past due, credit analysis factors, charge off criteria	30 days
Consumer, excluding credit card | Minimum
Impaired loans:
Number of payments under modified terms to recognize interest on cash basis	6
Consumer, excluding credit card | Home equity - senior lien
Impaired loans:
With an allowance	$ 552,000,000	$ 567,000,000
Without an allowance	549,000,000	579,000,000
Total impaired loans	1,101,000,000	1,146,000,000
Allowance for loan losses related to impaired loans	84,000,000	94,000,000
Unpaid principal balance of impaired loans	1,451,000,000	1,515,000,000
Average impaired loans	1,122,000,000	1,151,000,000	610,000,000
Interest income on impaired loans	55,000,000	59,000,000	27,000,000
Interest income on impaired loans on a cash basis	37,000,000	40,000,000	12,000,000
Consumer, excluding credit card | Home equity - senior lien | Permanent Modification | Regulatory Guidance Regarding Chapter 7 Loans
Impaired loans:
Rate of default for modified loans, estimated weighted average	19.00%
Consumer, excluding credit card | Home equity - senior lien | Nonaccrual
Impaired loans:
Total impaired loans	628,000,000	641,000,000
Consumer, excluding credit card | Home equity - junior lien
Impaired loans:
With an allowance	722,000,000	727,000,000
Without an allowance	582,000,000	592,000,000
Total impaired loans	1,304,000,000	1,319,000,000
Allowance for loan losses related to impaired loans	147,000,000	162,000,000
Unpaid principal balance of impaired loans	2,603,000,000	2,625,000,000
Period past due, credit analysis factors, charge off criteria	180 days
Average impaired loans	1,313,000,000	1,297,000,000	848,000,000
Interest income on impaired loans	82,000,000	82,000,000	42,000,000
Interest income on impaired loans on a cash basis	53,000,000	55,000,000	16,000,000
Consumer, excluding credit card | Home equity - junior lien | Permanent Modification | Regulatory Guidance Regarding Chapter 7 Loans
Impaired loans:
Rate of default for modified loans, estimated weighted average	12.00%
Consumer, excluding credit card | Home equity - junior lien | Nonaccrual
Impaired loans:
Total impaired loans	632,000,000	666,000,000
Consumer, excluding credit card | Mortgages - prime, including option ARMS
Impaired loans:
With an allowance	4,949,000,000	5,871,000,000
Without an allowance	1,196,000,000	1,133,000,000
Total impaired loans	6,145,000,000	7,004,000,000
Allowance for loan losses related to impaired loans	127,000,000	144,000,000
Unpaid principal balance of impaired loans	7,813,000,000	8,990,000,000
Average impaired loans	6,730,000,000	7,214,000,000	5,989,000,000
Interest income on impaired loans	262,000,000	280,000,000	238,000,000
Interest income on impaired loans on a cash basis	54,000,000	59,000,000	28,000,000
Consumer, excluding credit card | Mortgages - prime, including option ARMS | Permanent Modification | Regulatory Guidance Regarding Chapter 7 Loans
Impaired loans:
Rate of default for modified loans, estimated weighted average	25.00%
Consumer, excluding credit card | Mortgages - prime, including option ARMS | Nonaccrual
Impaired loans:
Total impaired loans	1,559,000,000	1,737,000,000
Consumer, excluding credit card | Mortgages - subprime
Impaired loans:
With an allowance	2,239,000,000	2,989,000,000
Without an allowance	639,000,000	709,000,000
Total impaired loans	2,878,000,000	3,698,000,000
Allowance for loan losses related to impaired loans	64,000,000	94,000,000
Unpaid principal balance of impaired loans	4,200,000,000	5,461,000,000
Average impaired loans	3,444,000,000	3,798,000,000	3,494,000,000
Interest income on impaired loans	182,000,000	200,000,000	183,000,000
Interest income on impaired loans on a cash basis	51,000,000	55,000,000	31,000,000
Consumer, excluding credit card | Mortgages - subprime | Permanent Modification | Regulatory Guidance Regarding Chapter 7 Loans
Impaired loans:
Rate of default for modified loans, estimated weighted average	18.00%
Consumer, excluding credit card | Mortgages - subprime | Nonaccrual
Impaired loans:
Total impaired loans	931,000,000	1,127,000,000
Consumer, excluding credit card | Residential real estate – excluding PCI
Impaired loans:
With an allowance	8,462,000,000	10,154,000,000
Without an allowance	2,966,000,000	3,013,000,000
Total impaired loans	11,428,000,000	13,167,000,000
Allowance for loan losses related to impaired loans	422,000,000	494,000,000
Unpaid principal balance of impaired loans	16,067,000,000	18,591,000,000
Loans modified subsequent to repurchase from Ginnie Mae	4,900,000,000	7,600,000,000
Average impaired loans	12,609,000,000	13,460,000,000	10,941,000,000
Interest income on impaired loans	581,000,000	621,000,000	490,000,000
Interest income on impaired loans on a cash basis	195,000,000	209,000,000	87,000,000
Number of payments under modified terms to recognize interest on cash basis	6
Consumer, excluding credit card | Residential real estate – excluding PCI | Current, and Less Than 90 Days Past Due
Impaired loans:
Period past due, credit analysis factors, charge off criteria	90 days
TDRs not having yet made six payments	2,900,000,000	3,000,000,000
Consumer, excluding credit card | Residential real estate – excluding PCI | Nonaccrual
Impaired loans:
Total impaired loans	$ 3,750,000,000	$ 4,171,000,000
Consumer, excluding credit card | Residential real estate – excluding PCI | Minimum | Days Past Due, 30 or More | Regulatory Guidance Regarding Chapter 7 Loans
Impaired loans:
Period past due, credit analysis factors, charge off criteria	30 days