Derivative Financial Instruments Netting of Financial Instruments - Derivatives (Details) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 6,598	$ 4,465
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement		6,598	4,465
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset		4,929	3,313
Derivative Assets	[1]	1,669	1,152
Collateral Held by The Company Against Derivative Asset Positions		130	66
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		1,539	1,086
Derivative Liability, Fair Value, Gross Liability		5,891	4,428
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement		5,891	4,428
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset		5,433	3,964
Derivative Liabilities	[2]	458	464
Derivative, Collateral, Right to Reclaim Securities		29	19
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		429	445
Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		6,202	4,184
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset		4,766	3,156
Derivative Assets		1,436	1,028
Collateral Held by The Company Against Derivative Asset Positions		130	66
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		1,306	962
Derivative Liability, Fair Value, Gross Liability		5,627	4,162
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset		5,270	3,807
Derivative Liabilities		357	355
Derivative, Collateral, Right to Reclaim Securities		29	19
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		328	336
Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		73	21
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset		0	0
Derivative Assets		73	21
Collateral Held by The Company Against Derivative Asset Positions		0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		73	21
Derivative Liability, Not Subject to Master Netting Arrangement		101	105
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset		0	0
Derivative Liabilities		101	105
Derivative, Collateral, Right to Reclaim Securities		0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		101	105
Exchange Traded [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		323	260
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset		163	157
Derivative Assets		160	103
Collateral Held by The Company Against Derivative Asset Positions		0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		160	103
Derivative Liability, Fair Value, Gross Liability		163	161
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset		163	157
Derivative Liabilities		0	4
Derivative, Collateral, Right to Reclaim Securities		0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		$ 0	$ 4

[1] At June 30, 2016, $1.7 billion, net of $786 million offsetting cash collateral, is recognized in trading assets and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2015, $1.2 billion, net of $397 million offsetting cash collateral, is recognized in trading assets and derivative instruments within the Company's Consolidated Balance Sheets.

[2] At June 30, 2016, $458 million, net of $1.3 billion offsetting cash collateral, is recognized in trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2015, $464 million, net of $1.0 billion offsetting cash collateral, is recognized in trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets.