Fair Value Measurements Level 4 Fair Value Option (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 199,248	$ 227,776
Fair Value, Option, Changes in Fair Value, Gain (Loss)	11	(6)
Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	348	0
Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	488	844
Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(3)	0
Asset-backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	15	3
Corporate Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(3)	(13)
Corporate Debt Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	133	92
Collateralized Debt Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	18	11
Collateralized Debt Obligations [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	69	183
Commercial Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	22	8
Foreign Government Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	(4)
Foreign Government Debt Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	30	518
Residential Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(1)	0
Residential Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	215	15
US Treasury Bond Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	2	24
Municipal Bonds [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	2	1
Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 14	$ (6)