Fair Value, Assets Recorded at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages held for sale	$ 21,539	$ 15,565
Loans held for sale	0	1
Loans	5,651	5,788
Other assets, carried at fair value	2,636	2,512
Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages held for sale	3,100	3,295
Loans held for sale	15	0
Loans	1,029	2,266
Other assets, carried at fair value	676	877
Nonrecurring [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	102	243
Nonrecurring [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	927	2,023
Level 1 [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages held for sale	0	0
Loans held for sale	0	0
Loans	0	0
Other assets, carried at fair value	0	0
Level 1 [Member] | Nonrecurring [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Level 1 [Member] | Nonrecurring [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Level 2 [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages held for sale	2,145	2,197
Loans held for sale	15	0
Loans	1,022	2,261
Other assets, carried at fair value	271	417
Level 2 [Member] | Nonrecurring [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	102	243
Level 2 [Member] | Nonrecurring [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	920	2,018
Level 3 [Member] | Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages held for sale	955	1,098
Loans held for sale	0	0
Loans	7	5
Other assets, carried at fair value	405	460
Level 3 [Member] | Nonrecurring [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Level 3 [Member] | Nonrecurring [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 7	$ 5