Investments (Details 12) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Total mortgage loans	$ 6,956	$ 6,956	$ 6,679
Mortgage loans, non-impaired
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Fixed rate mortgage loans	6,448	6,448	5,923
Variable rate mortgage loans	237	237	567
Total mortgage loans	6,685	6,685	6,490
Net carrying value of impaired mortgage loans
Impaired mortgage loans with a valuation allowance	257	257	168
Impaired loans without a valuation allowance	14	14	21
Total impaired mortgage loans	271	271	189
Valuation allowance on impaired mortgage loans	70	70
Average carrying value and interest income recognized on impaired mortgage loans
Average impaired mortgage loans		201
Rollforward of the valuation allowance on impaired mortgage loans
Valuation allowance on impaired mortgage loans, beginning balance	68	84
Net increase in valuation allowance	29	42
Charge offs	(27)	(56)
Valuation allowance on impaired mortgage loans, ending balance	70	70
Carrying value of past due mortgage loans
Less than 90 days past due			12
90 days or greater past due	64	64	78
Total past due	64	64	90
Financing Receivable, Recorded Investment, Current	6,892	6,892	6,589
Mortgage loans, non-impaired \| Below 1.0
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Fixed rate mortgage loans	277	277	280
Total mortgage loans	277	277	280
Mortgage loans, non-impaired \| 1.0 - 1.25
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Fixed rate mortgage loans	1,699	1,699	1,583
Variable rate mortgage loans			16
Total mortgage loans	1,699	1,699	1,599
Mortgage loans, non-impaired \| 1.26 - 1.50
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Fixed rate mortgage loans	1,584	1,584	1,520
Variable rate mortgage loans	69	69	5
Total mortgage loans	1,653	1,653	1,525
Mortgage loans, non-impaired \| Above 1.50
Carrying value of non-impaired mortgage loans, summarized by debt service coverage ratio distribution
Fixed rate mortgage loans	2,888	2,888	2,540
Variable rate mortgage loans	168	168	546
Total mortgage loans	$ 3,056	$ 3,056	$ 3,086

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Financing receivables that are less than 90 days past due.

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A valuation allowance for financing receivables that are expected to be uncollectible.

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Charge to expense for financing receivables that are expected to be uncollectible.

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Reduction to the allowance for credit losses related to financing receivables deemed uncollectible.

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Financing receivables that are current.

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Financing receivables that are equal to or greater than 90 days past due.

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Recorded Investment in financing receivables that are past due at the balance sheet date.

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The average recorded investment related to impaired financing receivables.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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