Pension and Other Postretirement Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Health care cost trend rate [Abstract]
Expected pre-65 health care cost trend rate, for next year	8.50%
Expected post-65 health care cost trend rate, for next year	8.50%
Expected pension plans expense [Abstract]
Expected U.S. pension plans expense, for next year	$ 13,000,000
Expected U.K. pension plan expense, for next year	2,000,000
Average pounds sterling to U.S. dollar exchange rate used to determine expected U.K. pension plan expense, for next year	1.56
Estimated amount of amortization from accumulated OCI into net periodic benefit expense [Abstract]
Estimated amount of amortization from accumulated OCI into net periodic benefit expense, next year	(26,000,000)
Pension and Other Postretirement Benefit Contributions [Abstract]
Pension Contributions	25,000,000
U.S. pension plan assets [Member]
Change in Plan Assets
Fair value as of beginning-of-year	918,000,000	842,000,000
Actual return on plan assets	72,000,000	118,000,000
Company and participant contributions	36,000,000	31,000,000
Benefits paid	(70,000,000)	(73,000,000)
Medicare Part D subsidy	0	0
Foreign exchange translation	0	0
Fair value as of end-of-year	956,000,000	918,000,000	842,000,000
Change in Benefit Obligation
Balance as of beginning-of-year	1,093,000,000	1,050,000,000
Service cost	3,000,000	3,000,000	(3,000,000)
Interest cost	58,000,000	61,000,000	(62,000,000)
Plan participants' contributions	0	0
Curtailments	0	0
Actuarial (gains) losses	154,000,000	52,000,000
Benefits paid	70,000,000	73,000,000
Medicare Part D subsidy	0	0
Foreign exchange translation	0	0
Balance as of end-of-year	1,238,000,000	1,093,000,000	1,050,000,000
Funded status of the plans	(282,000,000)	(175,000,000)
Amounts Recognized on the Consolidated Balance Sheets
Other assets	18,000,000	15,000,000
Other liabilities	(300,000,000)	(190,000,000)
Net amount recognized	(282,000,000)	(175,000,000)
Amounts Recognized in Accumulated OCI, Net of Tax
Net (gain) loss	243,000,000	153,000,000
Prior service credit	0	0
Net amount recognized	243,000,000	153,000,000
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate used in calculating benefit obligations	4.45%	5.50%
Expected return on plan assets used in calculating benefit obligations	7.78%	8.00%
Weighted-Average Assumptions, Net periodic benefit cost:
Weighted-average discount rate used in calculating net periodic benefit cost	5.45%	6.00%
Expected return on plan assets used in calculating net periodic benefit cost	7.78%	8.00%
Accumulated benefit obligation in excess of plan assets [Abstract]
Accumulated benefit obligation	1,118,000,000	1,072,000,000
Projected benefit obligation	1,118,000,000	1,072,000,000
Fair value of plan assets	818,000,000	881,000,000
Components of net defined benefit pension plan and postretirement benefit plan expense [Abstract]
Service cost	(3,000,000)	(3,000,000)	3,000,000
Interest cost	(58,000,000)	(61,000,000)	62,000,000
Expected return on plan assets	(71,000,000)	(65,000,000)	(55,000,000)
Amortization of prior service cost	0	0	0
Recognized net actuarial loss (gain)	13,000,000	15,000,000	28,000,000
Net periodic benefit expense (recovery)	3,000,000	14,000,000	38,000,000
U.S. pension plan assets [Member] | Fixed maturity securities [Member] | Employees [Member]
Pension plan target allocations by asset category [Abstract]
Debt securities	50.00%	50.00%
U.S. pension plan assets [Member] | Fixed maturity securities [Member] | Agents [Member]
Pension plan target allocations by asset category [Abstract]
Debt securities	80.00%	50.00%
U.S. pension plan assets [Member] | Corporate bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	370,000,000	266,000,000
U.S. pension plan assets [Member] | U.S. government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	114,000,000	103,000,000
U.S. pension plan assets [Member] | Foreign government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	24,000,000	39,000,000
U.S. pension plan assets [Member] | MBS CMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	4,000,000	5,000,000
U.S. pension plan assets [Member] | Equity securities [Member] | Employees [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	0.00%	0.00%
U.S. pension plan assets [Member] | Equity securities [Member] | Agents [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	0.00%	0.00%
U.S. pension plan assets [Member] | Common stock [Member]
Change in Plan Assets
Fair value as of end-of-year	418,000,000	444,000,000
U.S. pension plan assets [Member] | Common stock domestic large cap equity [Member] | Employees [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	35.00%	35.00%
U.S. pension plan assets [Member] | Common stock domestic large cap equity [Member] | Agents [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	14.00%	35.00%
U.S. pension plan assets [Member] | Common stock international equity [Member] | Employees [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	15.00%	15.00%
U.S. pension plan assets [Member] | Common stock international equity [Member] | Agents [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	6.00%	15.00%
U.S. pension plan assets [Member] | Cash and invested cash [Member]
Change in Plan Assets
Fair value as of end-of-year	24,000,000	58,000,000
U.S. pension plan assets [Member] | Cash and invested cash [Member] | Employees [Member]
Pension plan target allocations by asset category [Abstract]
Other assets	0.00%	0.00%
U.S. pension plan assets [Member] | Cash and invested cash [Member] | Agents [Member]
Pension plan target allocations by asset category [Abstract]
Other assets	0.00%	0.00%
U.S. pension plan assets [Member] | RMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	1,000,000	2,000,000
U.S. pension plan assets [Member] | CDOs [Member]
Change in Plan Assets
Fair value as of end-of-year	1,000,000	1,000,000
U.S. pension plan assets [Member] | Qualified Plans [Member]
Estimated future benefit payments [Abstract]
2012	72,000,000
2013	70,000,000
2014	68,000,000
2015	67,000,000
2016	69,000,000
Following five years thereafter	336,000,000
U.S. pension plan assets [Member] | Nonqualified Plans [Member]
Estimated future benefit payments [Abstract]
2012	10,000,000
2013	10,000,000
2014	9,000,000
2015	11,000,000
2016	9,000,000
Following five years thereafter	44,000,000
Non-U.S. Pension Benefits [Member]
Change in Plan Assets
Fair value as of beginning-of-year	314,000,000	307,000,000
Actual return on plan assets	49,000,000	29,000,000
Company and participant contributions	1,000,000	0
Benefits paid	(12,000,000)	(12,000,000)
Medicare Part D subsidy	0	0
Foreign exchange translation	(2,000,000)	(10,000,000)
Fair value as of end-of-year	350,000,000	314,000,000	307,000,000
Change in Benefit Obligation
Balance as of beginning-of-year	271,000,000	289,000,000
Service cost	0	0	(1,000,000)
Interest cost	15,000,000	16,000,000	(16,000,000)
Plan participants' contributions	0	0
Curtailments	0	0
Actuarial (gains) losses	38,000,000	(12,000,000)
Benefits paid	12,000,000	12,000,000
Medicare Part D subsidy	0	0
Foreign exchange translation	(1,000,000)	(10,000,000)
Balance as of end-of-year	311,000,000	271,000,000	289,000,000
Funded status of the plans	39,000,000	43,000,000
Amounts Recognized on the Consolidated Balance Sheets
Other assets	39,000,000	43,000,000
Other liabilities	0	0
Net amount recognized	39,000,000	43,000,000
Amounts Recognized in Accumulated OCI, Net of Tax
Net (gain) loss	33,000,000	30,000,000
Prior service credit	0	0
Net amount recognized	33,000,000	30,000,000
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate used in calculating benefit obligations	5.00%	5.70%
Expected return on plan assets used in calculating benefit obligations	5.40%	5.40%
Weighted-Average Assumptions, Net periodic benefit cost:
Weighted-average discount rate used in calculating net periodic benefit cost	5.70%	5.80%
Expected return on plan assets used in calculating net periodic benefit cost	5.40%	5.80%
Components of net defined benefit pension plan and postretirement benefit plan expense [Abstract]
Service cost	0	0	1,000,000
Interest cost	(15,000,000)	(16,000,000)	16,000,000
Expected return on plan assets	(16,000,000)	(16,000,000)	(15,000,000)
Amortization of prior service cost	0	0	1,000,000
Recognized net actuarial loss (gain)	0	1,000,000	1,000,000
Net periodic benefit expense (recovery)	(1,000,000)	1,000,000	4,000,000
Non-U.S. Pension Benefits [Member] | Fixed maturity securities [Member]
Pension plan target allocations by asset category [Abstract]
Debt securities	56.00%	65.00%
Non-U.S. Pension Benefits [Member] | Corporate bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	34,000,000	22,000,000
Non-U.S. Pension Benefits [Member] | U.S. government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	13,000,000	2,000,000
Non-U.S. Pension Benefits [Member] | Foreign government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	206,000,000	166,000,000
Non-U.S. Pension Benefits [Member] | MBS CMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Non-U.S. Pension Benefits [Member] | Equity securities [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	43.00%	15.00%
Non-U.S. Pension Benefits [Member] | Common stock [Member]
Change in Plan Assets
Fair value as of end-of-year	57,000,000	101,000,000
Non-U.S. Pension Benefits [Member] | Common stock domestic large cap equity [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	0.00%	0.00%
Non-U.S. Pension Benefits [Member] | Common stock international equity [Member]
Pension plan target allocations by asset category [Abstract]
Equity securities	0.00%	0.00%
Non-U.S. Pension Benefits [Member] | Cash and invested cash [Member]
Change in Plan Assets
Fair value as of beginning-of-year	21,000,000
Fair value as of end-of-year	39,000,000	21,000,000
Pension plan target allocations by asset category [Abstract]
Other assets	1.00%	20.00%
Non-U.S. Pension Benefits [Member] | RMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Non-U.S. Pension Benefits [Member] | CDOs [Member]
Change in Plan Assets
Fair value as of end-of-year	1,000,000	2,000,000
Non-U.S. Pension Benefits [Member] | Qualified Plans [Member]
Estimated future benefit payments [Abstract]
2012	12,000,000
2013	13,000,000
2014	14,000,000
2015	14,000,000
2016	15,000,000
Following five years thereafter	86,000,000
Other Postretirement Benefits [Member]
Change in Plan Assets
Fair value as of beginning-of-year	37,000,000	34,000,000
Actual return on plan assets	3,000,000	2,000,000
Company and participant contributions	15,000,000	15,000,000
Benefits paid	(17,000,000)	(15,000,000)
Medicare Part D subsidy	(1,000,000)	(1,000,000)
Foreign exchange translation	0	0
Fair value as of end-of-year	39,000,000	37,000,000	34,000,000
Change in Benefit Obligation
Balance as of beginning-of-year	155,000,000	151,000,000
Service cost	4,000,000	3,000,000	(3,000,000)
Interest cost	7,000,000	9,000,000	(8,000,000)
Plan participants' contributions	6,000,000	6,000,000
Curtailments	0	0
Actuarial (gains) losses	5,000,000	0
Benefits paid	17,000,000	15,000,000
Medicare Part D subsidy	(1,000,000)	(1,000,000)
Foreign exchange translation	0	0
Balance as of end-of-year	161,000,000	155,000,000	151,000,000
Funded status of the plans	(122,000,000)	(118,000,000)
Amounts Recognized on the Consolidated Balance Sheets
Other assets	0	0
Other liabilities	(122,000,000)	(118,000,000)
Net amount recognized	(122,000,000)	(118,000,000)
Amounts Recognized in Accumulated OCI, Net of Tax
Net (gain) loss	5,000,000	2,000,000
Prior service credit	(3,000,000)	(4,000,000)
Net amount recognized	2,000,000	(2,000,000)
Rate of Increase in Compensation
Retiree Life Insurance Plan	4.00%	4.00%
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate used in calculating benefit obligations	4.25%	5.00%
Expected return on plan assets used in calculating benefit obligations	6.50%	6.50%
Weighted-Average Assumptions, Net periodic benefit cost:
Weighted-average discount rate used in calculating net periodic benefit cost	5.00%	6.00%
Expected return on plan assets used in calculating net periodic benefit cost	6.50%	6.50%
Health care cost trend rate [Abstract]
Pre-65 health care cost trend rate	8.50%	9.50%	10.00%
Post-65 health care cost trend rate	8.50%	9.50%	13.00%
Ultimate trend rate	4.50%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2021	2020	2020
Effect of one-percentage point change in assumed health care cost trend rates [Abstract]
Effect of one-percentage point increase in assumed health care cost trend rates on accumulated postretirement benefit obligation	5,000,000
Effect of one-percentage point increase in assumed health care cost trend rates on total service and interest cost components	1,000,000
Effect of one-percentage point decrease in assumed health care cost trend rates on accumulated postretirement benefit obligation	(8,000,000)
Effect of one-percentage point decrease in assumed health care cost trend rates on total service and interest cost components	(1,000,000)
Components of net defined benefit pension plan and postretirement benefit plan expense [Abstract]
Service cost	(4,000,000)	(3,000,000)	3,000,000
Interest cost	(7,000,000)	(9,000,000)	8,000,000
Expected return on plan assets	(2,000,000)	(2,000,000)	(2,000,000)
Amortization of prior service cost	(1,000,000)	(1,000,000)	(1,000,000)
Recognized net actuarial loss (gain)	1,000,000	1,000,000	(2,000,000)
Net periodic benefit expense (recovery)	9,000,000	10,000,000	6,000,000
Other Postretirement Benefits [Member] | Corporate bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | U.S. government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | Foreign government bonds [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | MBS CMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | Common stock [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | Cash and invested cash [Member]
Change in Plan Assets
Fair value as of end-of-year	39,000,000	37,000,000
Other Postretirement Benefits [Member] | RMBS [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | CDOs [Member]
Change in Plan Assets
Fair value as of end-of-year	0	0
Other Postretirement Benefits [Member] | U.S. Plans Reflecting Medicare Part D Subsidy [Member]
Estimated future benefit payments [Abstract]
2012	10,000,000
2013	10,000,000
2014	11,000,000
2015	11,000,000
2016	12,000,000
Following five years thereafter	59,000,000
Other Postretirement Benefits [Member] | U.S. Medicare Part D Subsidy [Member]
Estimated future benefit payments [Abstract]
2012	(2,000,000)
2013	(2,000,000)
2014	(2,000,000)
2015	(2,000,000)
2016	(2,000,000)
Following five years thereafter	(12,000,000)
Other Postretirement Benefits [Member] | U.S. Plans Not Reflecting Medicare Part D Subsidy [Member]
Estimated future benefit payments [Abstract]
2012	12,000,000
2013	12,000,000
2014	13,000,000
2015	13,000,000
2016	14,000,000
Following five years thereafter	$ 71,000,000