Fair Value Measurements Level 4 Fair Value Option (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		$ 181,633	$ 199,248
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(16)	11
Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	[1]	282	348
Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		503	488
Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(12)	(3)
Asset-backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		13	15
Corporate Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(7)	(3)
Corporate Debt Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		87	133
Collateralized Debt Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		1	18
Collateralized Debt Obligations [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		6	69
Commercial Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		24	22
Foreign Government Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		2	0
Foreign Government Debt Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		2	30
Residential Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		0	(1)
Residential Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		368	215
US Treasury Bond Securities [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		3	2
Municipal Bonds [Member] | Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure		0	2
Fixed Maturities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		$ (4)	$ 14

[1] [1] Included in equity securities, AFS on the Consolidated Balance Sheets.