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Derivatives - Narrative (Details) | 12 Months Ended
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Dec. 31, 2018 USD ($) swap | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Carrying value of collateral received to support purchased call options | $ 103,000,000 | $ 389,000,000 |
Not Designated as Hedging Instrument | Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
The portion of the change in fair value of the embedded derivative related to the unlocking of actuarial assumptions | (44,000,000) | (25,000,000) | $ (17,000,000)
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Notional amount of derivative instrument outstanding | $ 2,350,000,000.00 | 1,580,000,000.00 |
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Number of interest rate swaps designated and qualifying as a cash flow hedges | swap | 16 |  |
Number of interest rate swaps entered into during the period | swap | 6 |  |
Gain (loss) reclassified from AOCI into net investment income | $ (3,000,000) | 6,000,000 | 7,000,000
Gain (loss) on cash flow hedge ineffectiveness recorded in Net Earnings | 0 | 0 | $ 0
Collateral receivable supporting interest rate swaps | 135,000,000 | 70,000,000 |
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other assets |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Net derivatives, at fair value | 16,000,000 |  |
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other assets | Maximum |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Net derivatives, at fair value |  | 1,000,000 |
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other liabilities |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Net derivatives, at fair value | (46,000,000) | $ (31,000,000) |
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | New interest rate swaps entered into during the period |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Notional amount of derivative instrument outstanding | $ 911,000,000 |  |

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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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959 + Details
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- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41678-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611 + Details
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