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Derivatives - Gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
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Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | $ (36) | $ (35) | $ (15) | $ (42)
MBS with embedded derivatives | Realized gains (losses) on securities |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | (1) | (3) | (5) | (3)
Public company warrants | Realized gains (losses) on securities |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | 0 | 0 | (1) | 0
Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative | [1] | (126) | (112) | (63) | (259)
Equity index call options | Annuity benefits |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | 90 | 81 | 52 | 222
Equity index put options | Annuity benefits |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | 0 | 0 | 0 | 0
Reinsurance contracts (embedded derivative) | Net investment income |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net [Abstract] |  |  |  |  |
Derivative |  | $ 1 | $ (1) | $ 2 | $ (2)
[1] | The change in fair value of the embedded derivative includes losses related to unlocking of actuarial assumptions of $44 million in both the second quarter and first six months of 2018

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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- References No definition available. + Details
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