Investments - Appreciation (Depreciation) on Fixed Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 15,267	$ 15,465
Unrealized Appreciation	1,312	2,254
Unrealized (Depreciation)	(99)	(30)
Total Fair Value	16,480	17,689
Commitments to purchase fixed maturities	56
Run-off Settlement Annuity Business [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Appreciation	478	883
Unrealized (Depreciation)	(20)	(8)
Total Fair Value	2,600	3,100
Federal government and agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	640	509
Unrealized Appreciation	242	393
Unrealized (Depreciation)	(2)	0
Total Fair Value	880	902
State and local government [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,983	2,169
Unrealized Appreciation	167	270
Unrealized (Depreciation)	(6)	(2)
Total Fair Value	2,144	2,437
Foreign government [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,392	1,197
Unrealized Appreciation	64	126
Unrealized (Depreciation)	(12)	(1)
Total Fair Value	1,444	1,322
Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,301	10,590
Unrealized Appreciation	749	1,308
Unrealized (Depreciation)	(74)	(17)
Total Fair Value	10,976	11,881
Federal agency mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	77	121
Unrealized Appreciation	0	1
Unrealized (Depreciation)	(1)	0
Total Fair Value	76	122
Other mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	76	82
Unrealized Appreciation	3	11
Unrealized (Depreciation)	(2)	(4)
Total Fair Value	77	89
Other asset-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	798	797
Unrealized Appreciation	87	145
Unrealized (Depreciation)	(2)	(6)
Total Fair Value	$ 883	$ 936