Fair Value Measurement - Level 3 Inputs (Details) (USD $)	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(2,061,000,000)	$ 326,000,000	$ 1,893,000,000	$ 6,238,000,000
Option pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Interest rate spread volatility	60.00%
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	626,000,000	2,379,000,000	3,322,000,000	3,561,000,000
Interest rate contracts | Option pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Interest rate correlation	(75.00%)
Interest rate spread volatility	0.00%
Interest rate contracts | Option pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Interest rate correlation	95.00%
Interest rate spread volatility	60.00%
Credit derivatives
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	189,000,000	95,000,000	1,873,000,000	7,732,000,000
Credit derivatives | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Credit correlation	47.00%
Credit derivatives | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Credit correlation	90.00%
Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(526,000,000)	(1,200,000,000)	(1,750,000,000)	(1,263,000,000)
Foreign exchange contracts | Option pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Foreign exchange correlation	0.00%
Foreign exchange contracts | Option pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Foreign exchange correlation	60.00%
Equity
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(1,785,000,000)	(1,063,000,000)	(1,806,000,000)	(3,105,000,000)
Equity | Option pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity volatility	15.00%
Equity | Option pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity volatility	65.00%
Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(565,000,000)	115,000,000	254,000,000	(687,000,000)
Commodity contracts | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Forward commodity price	90
Long-term debt, other borrowed funds, and deposits | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Credit correlation	47.00%
Long-term debt, other borrowed funds, and deposits | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Credit correlation	90.00%
Long-term debt, other borrowed funds, and deposits | Option pricing | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Interest rate correlation	(75.00%)
Interest rate spread volatility	0.00%
Foreign exchange correlation	0.00%
Equity correlation	(55.00%)
Long-term debt, other borrowed funds, and deposits | Option pricing | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Interest rate correlation	95.00%
Foreign exchange correlation	60.00%
Equity correlation	85.00%
Residential mortgage-backed securities and loans | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	1.00%
Prepayment rate	0.00%
Conditional default rate	0.00%
Loss severity	0.00%
Residential mortgage-backed securities and loans | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	25.00%
Prepayment rate	18.00%
Conditional default rate	100.00%
Loss severity	90.00%
Residential mortgage-backed securities and loans | Discounted cash flows | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	5.00%
Prepayment rate	6.00%
Conditional default rate	22.00%
Loss severity	27.00%
Commercial mortgage-backed securities and loans | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	2.00%
Conditional default rate	0.00%
Loss severity	0.00%
Commercial mortgage-backed securities and loans | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	32.00%
Conditional default rate	100.00%
Loss severity	50.00%
Commercial mortgage-backed securities and loans | Discounted cash flows | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	5.00%
Conditional default rate	8.00%
Loss severity	29.00%
Corporate debt securities, obligations of U.S. states and municipalities, and other | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	1.00%
Credit spread	0.53%
Corporate debt securities, obligations of U.S. states and municipalities, and other | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	22.00%
Credit spread	2.70%
Corporate debt securities, obligations of U.S. states and municipalities, and other | Discounted cash flows | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate	7.00%
Credit spread	1.40%
Corporate debt securities, obligations of U.S. states and municipalities, and other | Market comparables | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	0
Corporate debt securities, obligations of U.S. states and municipalities, and other | Market comparables | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	131
Corporate debt securities, obligations of U.S. states and municipalities, and other | Market comparables | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	90
Asset-backed securities, Collateralized loan obligations | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Conditional default rate	2.00%
Loss severity	40.00%
Asset-backed securities, Collateralized loan obligations | Discounted cash flows | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Prepayment rate	20.00%
Credit spread	2.60%
Asset-backed securities, Collateralized loan obligations | Discounted cash flows | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Credit spread	6.75%
Asset-backed securities, Collateralized loan obligations | Discounted cash flows | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Prepayment rate	20.00%
Conditional default rate	2.00%
Loss severity	40.00%
Credit spread	2.79%
Asset-backed securities, Collateralized loan obligations | Market comparables | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	0
Asset-backed securities, Collateralized loan obligations | Market comparables | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	146
Asset-backed securities, Collateralized loan obligations | Market comparables | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Price	79
Private equity | Private equity direct investments | Market comparables | Minimum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liquidity adjustment	0.00%
EBITDA multiple	6
Private equity | Private equity direct investments | Market comparables | Maximum
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liquidity adjustment	15.00%
EBITDA multiple	12.4
Private equity | Private equity direct investments | Market comparables | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liquidity adjustment	7.00%
EBITDA multiple	9.1
Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liability fair value	211,764,000,000	193,999,000,000
Level 3 Analysis - Supplemental Data:
Trading Securities	320,013,000,000	308,905,000,000
Trading liabilities	152,815,000,000	137,744,000,000
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liability fair value	32,069,000,000	33,958,000,000
Level 3 Analysis - Supplemental Data:
Trading Securities	22,489,000,000	27,224,000,000
Trading liabilities	14,698,000,000	18,356,000,000
Recurring | Level 3 | Interest rate contracts | Option pricing
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	626,000,000
Recurring | Level 3 | Credit derivatives | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	189,000,000
Recurring | Level 3 | Foreign exchange contracts | Option pricing
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(526,000,000)
Recurring | Level 3 | Equity | Option pricing
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(1,785,000,000)
Recurring | Level 3 | Commodity contracts | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivative asset (liability)	(565,000,000)
Recurring | Level 3 | Long-term debt, other borrowed funds, and deposits | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liability fair value	1,120,000,000
Recurring | Level 3 | Long-term debt, other borrowed funds, and deposits | Option pricing
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liability fair value	15,069,000,000
Recurring | Level 3 | Credit derivatives with underlying mortgage risk
Level 3 Analysis - Supplemental Data:
Trading liabilities	433,000,000
Recurring | Level 3 | Credit derivatives with underlying asset-backed securities risk
Level 3 Analysis - Supplemental Data:
Trading liabilities	715,000,000
Recurring | Level 3 | Residential mortgage-backed securities and loans | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	8,917,000,000
Recurring | Level 3 | Commercial mortgage-backed securities and loans | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	5,319,000,000
Recurring | Level 3 | Corporate debt securities, obligations of U.S. states and municipalities, and other | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	6,387,000,000
Recurring | Level 3 | Corporate debt securities, obligations of U.S. states and municipalities, and other | Market comparables
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	6,629,000,000
Recurring | Level 3 | Asset-backed securities, Collateralized loan obligations | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	792,000,000
Recurring | Level 3 | Asset-backed securities, Collateralized loan obligations | Market comparables
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	393,000,000
Recurring | Level 3 | Mortgage servicing rights | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	7,436,000,000
Recurring | Level 3 | Private equity | Private equity direct investments | Market comparables
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	2,054,000,000
Recurring | Level 3 | Private equity | Private equity fund investments | Net asset value
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Asset fair value	421,000,000
Recurring | Level 3 | Credit derivatives with underlying mortgage risk
Level 3 Analysis - Supplemental Data:
Trading Securities	491,000,000
Recurring | Level 3 | Credit derivatives with underlying asset-backed securities risk
Level 3 Analysis - Supplemental Data:
Trading Securities	795,000,000