Statutory Net Income and Surplus and Dividend Restrictions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
statutorydisclosures[LineItems]
statutoryaccountingpracticesstatutorynetincome					$ 406	$ 217	$ 177
Statutory Surplus Balance		448			443	448
StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPayments					143
OrdinaryDividend							318
ExtraordinaryDividend	$ 184	$ 160	$ 248	$ 270	$ 100