Related Party (Affiliated Asset Transfers) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2011	Mar. 31, 2012
Related Party Transactions [Abstract]
Fixed maturity asset transfer amortized cost	$ 143	$ 143	$ 123
Fixed maturity asset transfer fair value	151	151	141
Realized gain on fixed maturity asset transfer	8	8
Commercial mortgage loans asset transfer amortized cost	49
Commercial mortgage loans asset transfer fair value	54
Realized gain on commerical mortgage loan asset transfer	5
Asset Transfer APIC Change			$ 11