Fair Value Measurements Level 4 Fair Value Option (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	$ 198,246		$ 199,248
Fair Value, Option, Changes in Fair Value, Gain (Loss)	4	12
Corporate Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	2
Collateralized Debt Obligations [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	1	8
Foreign Government Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	1
Residential Mortgage Backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	1	1
Fixed Maturities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	2	12
Equity Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	2	0
Equity Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	402		348
Fixed Maturities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	520		488
Fixed Maturities [Member] | Asset-backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	15		15
Fixed Maturities [Member] | Corporate Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	135		133
Fixed Maturities [Member] | Collateralized Debt Obligations [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	72		69
Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	21		22
Fixed Maturities [Member] | Foreign Government Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	29		30
Fixed Maturities [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	242		215
Fixed Maturities [Member] | US Treasury Bond Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	5		2
Fixed Maturities [Member] | Municipal Bonds [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Assets Accounted for Using Fair Value Option	$ 1		$ 2