Fair Value Measurements Level 4 Fair Value Option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	$ 165	$ 280
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(12)	32
Asset-backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	4	13
Corporate Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	31	96
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(3)	(3)
Collateralized Debt Obligations [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	1	67
Fair Value, Option, Changes in Fair Value, Gain (Loss)	1	21
Commercial Mortgage Backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	6	15
Foreign Government Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	1	3
Fair Value, Option, Changes in Fair Value, Gain (Loss)	2	16
Municipal Bonds [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	0	2
Residential Mortgage Backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	119	82
Fixed Maturities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	34
US Treasury and Government [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	3	2
Equity Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	281	248
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ (12)
Credit Linked Notes [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		$ (2)