Commitments and Guarantees (Reinsurance Agreements Exposure and Reserves) (Details) (Reinsurance Agreements [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Loss Contingencies [Line Items]
Maximum Exposure	$ 5,731		$ 5,846
Excess of Loss - Mortgage Insurance	3.00%		3.00%
Quota Share	97.00%		97.00%
Reserves, Beginning balance	61	82
Paid Losses	(21)	(35)
Net Provision	8	23
Reserves, Ending balance	48	70
Accidental Death and Dismemberment [Member]
Loss Contingencies [Line Items]
Maximum Exposure	1,973		2,049
Credit Life, Accident and Health [Member]
Loss Contingencies [Line Items]
Maximum Exposure	674		795
Lender Placed Hazard [Member]
Loss Contingencies [Line Items]
Maximum Exposure	2,901		2,774
Borrower and Lender Paid Mortgage Insurance [Member]
Loss Contingencies [Line Items]
Maximum Exposure	183		228
Agreements With Full Reinsurance [Member]
Loss Contingencies [Line Items]
Maximum Exposure	$ 673		$ 794