Netting Arrangements Table (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets:
Derivative assets, gross amount	$ 6,643	$ 8,756
Derivative asset, gross amount offset	(5,186)	(8,422)
Derivative assets, net amount presented in the consolidated balance sheets	1,457	334
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	(116)	(83)
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(40)	(20)
Derivative assets, net amount	1,301	231
Securities purchased under agreements to resell, or similar arrangements, gross amount	47,550	50,565
Securities purchased under agreements to resell or similar arrangements, gross amount offset	0	0
Securities purchased under agreements to resell or similar arrangements, net amount presented in the consolidated balance sheets	47,550	50,565
Securities purchased under agreements to resell, under master netting arrangement, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Securities purchased under agreements to resell or similar arrangements, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(47,550)	(50,565)
Securities purchased under agreements to resell or similar arrangements, net amount	0	0
Total assets, gross amount	54,193	59,321
Total assets, gross amount offset	(5,186)	(8,422)
Total assets, net amount presented in the consolidated balance sheets	49,007	50,899
Total assets, under the master netting arrangements, not offset in the consolidated balance sheets, financial instruments	(116)	(83)
Total assets, under master netting arrangements, not offset in the consolidated balance sheets, collateral	(47,590)	(50,585)
Total assets, net amount	1,301	231
Liabilities:
Derivative liabilities, gross amount	(10,807)
Derivative liabilities, gross amount offset	10,194
Derivative liabilities, net amount presented in the consolidated balance sheets	(613)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	116
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0
Derivative liabilities, net amount	(497)
Securities sold under agreements to repurchase, gross amount	(50)
Securities sold under agreements to repurchase, gross amount offset	0
Securities sold under agreements to repurchase, net amount presented in the consolidated balance sheets	(50)
Securities sold under agreements to repurchase, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0
Securities sold under agreements to repurchase, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	50
Securities sold under agreements to repurchase, net amount	0
Total liabilities, gross amount	(10,857)	(9,717)
Total liabilities, gross amount offset	10,194	9,370
Total liabilities, net amount presented in the consolidated balance sheets	(663)	(347)
Total liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	116	83
Total liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	50	0
Total liabilities, net amount	(497)	(264)
OTC risk management derivatives [Member]
Assets:
Derivative asset, gross amount offset	(5,186)	(8,422)
Liabilities:
Derivative liabilities, gross amount offset	10,194	9,370
OTC risk management derivatives [Member] | OTC Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	5,461	8,491
Derivative asset, gross amount offset	(5,428)	(8,422)
Derivative assets, net amount presented in the consolidated balance sheets	33	69
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(33)	(20)
Derivative assets, net amount	0	49
Liabilities:
Derivative liabilities, gross amount	(7,836)	(9,503)
Derivative liabilities, gross amount offset	7,567	9,370
Derivative liabilities, net amount presented in the consolidated balance sheets	(269)	(133)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(269)	(133)
OTC risk management derivatives [Member] | OTC-Cleared Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	927
Derivative asset, gross amount offset	242
Derivative assets, net amount presented in the consolidated balance sheets	1,169
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0
Derivative assets, net amount	1,169
Liabilities:
Derivative liabilities, gross amount	(2,627)
Derivative liabilities, gross amount offset	2,627
Derivative liabilities, net amount presented in the consolidated balance sheets	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0
Derivative liabilities, net amount	0
Mortgage commitment derivatives [Member]
Assets:
Derivative assets, gross amount	255	265
Derivative asset, gross amount offset	0	0
Derivative assets, net amount presented in the consolidated balance sheets	255	265
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	(116)	(83)
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(7)	0
Derivative assets, net amount	132	182
Liabilities:
Derivative liabilities, gross amount	(344)	(214)
Derivative liabilities, gross amount offset	0	0
Derivative liabilities, net amount presented in the consolidated balance sheets	(344)	(214)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	116	83
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	$ (228)	$ (131)