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Derivatives - Narrative (Details) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 USD ($) swap | Mar. 31, 2018 USD ($) swap | Jun. 30, 2017 USD ($) | Jun. 30, 2018 USD ($) swap | Jun. 30, 2017 USD ($) | Dec. 31, 2017 USD ($)
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Carrying value of collateral received to support purchased call options | $ 353,000,000 |  |  | $ 353,000,000 |  | $ 389,000,000
Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Number of interest rate swaps designated and qualifying as a cash flow hedges | swap | 11 |  |  | 11 |  |
Notional amount of derivative instrument outstanding | $ 1,639,000,000 |  |  | $ 1,639,000,000 |  | 1,580,000,000
Gain (loss) reclassified from AOCI into net investment income | (2,000,000) |  | $ 1,000,000 | (1,000,000) | $ 3,000,000 |
Gain (loss) on cash flow hedge ineffectiveness recorded in Net Earnings | 0 |  | $ 0 | 0 | $ 0 |
Collateral receivable supporting interest rate swaps | 116,000,000 |  |  | 116,000,000 |  | 70,000,000
Other assets | Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Net derivatives, at fair value | 0 |  |  | 0 |  |
Other assets | Maximum | Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Net derivatives, at fair value |  |  |  |  |  | 1,000,000
Other liabilities | Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Net derivatives, at fair value | (70,000,000) |  |  | (70,000,000) |  | $ (31,000,000)
New interest rate swaps entered into during the period | Cash Flow Hedges | Designated as Hedging Instrument | Interest rate swaps |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Notional amount of derivative instrument outstanding |  | $ 130,000,000 |  |  |  |
Number of interest rate swaps entered into during the period | swap |  | 1 |  |  |  |
Annuity benefits | Not Designated as Hedging Instrument | Fixed-Indexed Annuities (Embedded Derivative) [Member] |  |  |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |  |  |
Total realized/unrealized gains (losses) included in net income for the embedded derivatives related to the unlocking of actuarial assumptions | $ (44,000,000) |  |  | $ (44,000,000) |  |

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624258-113959 + Details
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