Fair Value Measurements - Financial Assets and Financial Liabilities Carried at Fair Value (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Financial assets at fair value:
Fixed maturities	$ 16,486		$ 17,705
Equity securities	141		111
Short-term investments	631		154
Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	16,486	[1]	17,705	[2]
Equity securities	141		111
Subtotal	16,627		17,816
Short-term investments	631		154
Total financial assets at fair value, excluding separate accounts	18,012		18,633
Financial liabilities at fair value:
Total financial liabilities at fair value	757		1,201
Run-off Settlement Annuity Business [Member] | Fair Value, Measurements, Recurring [Member]
Financial liabilities at fair value:
Net appreciation required to adjust future policy benefits for run-off settlement annuity business included in fixed maturities	458		875
Other derivatives [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	3	[3]	41	[4]
Financial liabilities at fair value:
Derivative liabilities	16	[3]	31	[4]
Other derivatives [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	3		5
Financial liabilities at fair value:
Derivative liabilities	15		31
Other derivatives [Member] | Non designated [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	0		36
Financial liabilities at fair value:
Derivative liabilities	1		0
Guaranteed Minimum Income Benefit [Member]
Financial liabilities at fair value:
Percentage of GMIB exposure covered by retrocessional coverage	100.00%		55.00%
Number of external reinsurers	3		2
Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	751	[5]	622	[6]
Financial liabilities at fair value:
Derivative liabilities	741		1,170
Federal government and agency [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	880		902
State and local government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	2,144		2,437
Foreign government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	1,444		1,322
Corporate [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	10,981		11,896
Federal agency mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	76		122
Other mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	77		89
Other asset-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	884		937
Fair Value Inputs Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	297	[1]	156	[2]
Equity securities	8		4
Subtotal	305		160
Short-term investments	0		0
Total financial assets at fair value, excluding separate accounts	305		160
Financial liabilities at fair value:
Total financial liabilities at fair value	0		0
Fair Value Inputs Level 1 [Member] | Other derivatives [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	0	[3]	0	[4]
Financial liabilities at fair value:
Derivative liabilities	0	[3]	0	[4]
Fair Value Inputs Level 1 [Member] | Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	0	[5]	0	[6]
Financial liabilities at fair value:
Derivative liabilities	0		0
Fair Value Inputs Level 1 [Member] | Federal government and agency [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	297		156
Fair Value Inputs Level 1 [Member] | State and local government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 1 [Member] | Foreign government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 1 [Member] | Corporate [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 1 [Member] | Federal agency mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 1 [Member] | Other mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 1 [Member] | Other asset-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	15,058	[1]	16,232	[2]
Equity securities	74		73
Subtotal	15,132		16,305
Short-term investments	631		154
Total financial assets at fair value, excluding separate accounts	15,766		16,500
Financial liabilities at fair value:
Total financial liabilities at fair value	16		31
Fair Value Inputs Level 2 [Member] | Other derivatives [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	3	[3]	41	[4]
Financial liabilities at fair value:
Derivative liabilities	16	[3]	31	[4]
Fair Value Inputs Level 2 [Member] | Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	0	[5]	0	[6]
Financial liabilities at fair value:
Derivative liabilities	0		0
Fair Value Inputs Level 2 [Member] | Federal government and agency [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	583		746
Fair Value Inputs Level 2 [Member] | State and local government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	2,144		2,437
Fair Value Inputs Level 2 [Member] | Foreign government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	1,421		1,298
Fair Value Inputs Level 2 [Member] | Corporate [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	10,476		11,201
Fair Value Inputs Level 2 [Member] | Federal agency mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	76		122
Fair Value Inputs Level 2 [Member] | Other mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	76		88
Fair Value Inputs Level 2 [Member] | Other asset-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	282		340
Fair Value Inputs Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	1,131	[1]	1,317	[2]
Equity securities	59		34
Subtotal	1,190		1,351
Short-term investments	0		0
Total financial assets at fair value, excluding separate accounts	1,941		1,973
Financial liabilities at fair value:
Total financial liabilities at fair value	741		1,170
Fair Value Inputs Level 3 [Member] | Run-off Settlement Annuity Business [Member] | Fair Value, Measurements, Recurring [Member]
Financial liabilities at fair value:
Net appreciation required to adjust future policy benefits for run-off settlement annuity business included in fixed maturities	60		108
Fair Value Inputs Level 3 [Member] | Other derivatives [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	0	[3]	0	[4]
Financial liabilities at fair value:
Derivative liabilities	0	[3]	0	[4]
Fair Value Inputs Level 3 [Member] | Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Derivative assets	751	[5]	622	[6]
Financial liabilities at fair value:
Derivative liabilities	741		1,170
Fair Value Inputs Level 3 [Member] | Federal government and agency [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 3 [Member] | State and local government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 3 [Member] | Foreign government [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	23		24
Fair Value Inputs Level 3 [Member] | Corporate [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	505		695
Fair Value Inputs Level 3 [Member] | Federal agency mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	0		0
Fair Value Inputs Level 3 [Member] | Other mortgage-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	1		1
Fair Value Inputs Level 3 [Member] | Other asset-backed [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets at fair value:
Fixed maturities	$ 602		$ 597

[1] Fixed maturities included $458 million of net appreciation required to adjust future policy benefits for the run-off settlement annuity business including $60 million of appreciation for securities classified in Level 3.

[2] Fixed maturities included $875 million of net appreciation required to adjust future policy benefits for the run-off settlement annuity business including $108 million of appreciation for securities classified in Level 3.

[3] Other derivative assets reflected interest rate and foreign currency swaps qualifying as cash flow hedges. Other derivative liabilities included $15 million of interest rate and foreign currency swaps qualifying as cash flow hedges and $1 million of interest rate and foreign currency swaps not designated as accounting hedges. See Note 12 for additional information.

[4] Other derivative assets included $5 million of interest rate and foreign currency swaps qualifying as cash flow hedges and $36 million of interest rate swaps not designated as accounting hedges. Other derivative liabilities reflected foreign currency and interest rate swaps qualifying as cash flow hedges. See Note 12 for additional information.

[5] The GMIB assets represented retrocessional contracts in place from three external reinsurers that cover the exposures on these contracts. See Note 7 for additional information.

[6] The GMIB assets represented retrocessional contracts in place from two external reinsurers that cover 55% of the exposures on these contracts. See Note 7 for additional information.