Investments (Mortgage Loans and Valuation Allowance by Portfolio Segment) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Mortgage Loans on Real Estate [Line Items]
Unpaid Principal Balance	$ 57	$ 126
Recorded Investment	54	123
Valuation Allowances	10	26
Unpaid Principal Balance	206	155
Recorded Investment	197	150
Recorded Investment	63,094	59,562
Valuation Allowances	301	279
Carrying Value	241	247
Commercial
Mortgage Loans on Real Estate [Line Items]
Unpaid Principal Balance	7	75
Recorded Investment	7	75
Valuation Allowances	7	24
Unpaid Principal Balance	76	101
Recorded Investment	76	100
Recorded Investment	41,536	40,913
Valuation Allowances	208	200
Carrying Value	76	151
Agricultural
Mortgage Loans on Real Estate [Line Items]
Unpaid Principal Balance	50	51
Recorded Investment	47	48
Valuation Allowances	3	2
Unpaid Principal Balance	12	14
Recorded Investment	12	13
Recorded Investment	12,712	12,317
Valuation Allowances	38	37
Carrying Value	56	59
Residential
Mortgage Loans on Real Estate [Line Items]
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Valuation Allowances	0	0
Unpaid Principal Balance	118	40
Recorded Investment	109	37
Recorded Investment	8,846	6,332
Valuation Allowances	55	42
Carrying Value	$ 109	$ 37

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

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The balance of financing receivables that were collectively evaluated for impairment.

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Accounting Standards Codification

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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