Derivative Financial Instruments (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Asset derivatives
Asset derivatives gross amount	$ 168	$ 266
Derivative assets net amount on balance sheet	156	254
Liability derivatives
Liability derivatives gross amount	(669)	(752)
Derivative liabilities net amount on balance sheet	(661)	(741)
OTC derivatives
Asset derivatives
Asset derivatives gross amount	10	14
Offsets of derivative assets under counterparty netting	(8)	(11)
Derivative assets net amount on balance sheet	2	3
Derivative assets pledged under securities collateral	(2)	(3)
Liability derivatives
Liability derivatives gross amount	(30)	(33)
Offsets of derivative liabilities under counterparty netting	8	11
Derivative liability offsets under cash collateral pledged	(2)	(4)
Derivative liabilities net amount on balance sheet	(24)	(26)
Derivative liabilities received under securities collateral	20	22
Derivative liabilities net amount	$ (4)	$ (4)