Guarantees Mortgage Loans Repurchase Reserve Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Guarantees [Abstract]
Reserve For Mortgage Loan Repurchase Losses	$ 60	$ 77	$ 60	$ 77	$ 85	$ 82	$ 78	$ 83
Mortgage Repurchase Reserve, Provision for Mortgage Loan Repurchase Losses	(6)	(5)	(8)	(10)
Charge Offs For Mortgage Loan Repurchase Losses	$ 16	$ 11	$ 17	$ 11