Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Detail) - USD ($) $ in Millions |
6 Months Ended | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2018 |
Mar. 31, 2018 |
[2] | Dec. 31, 2017 |
Jun. 30, 2017 |
[3] | Mar. 31, 2017 |
[3] | Dec. 31, 2016 |
[3] | ||||||||||||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |||||||||||||||||||||
Fair Value Measurements, Valuation Techniques | [1] | Actuarial model | |||||||||||||||||||
Minimum [Member] | |||||||||||||||||||||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |||||||||||||||||||||
Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate | [1] | 3.00% | |||||||||||||||||||
Significant Unobservable Inputs Annuitization Rate | [1] | 0.00% | |||||||||||||||||||
Maximum [Member] | |||||||||||||||||||||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |||||||||||||||||||||
Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate | [1] | 33.00% | |||||||||||||||||||
Significant Unobservable Inputs Annuitization Rate | [1] | 100.00% | |||||||||||||||||||
Guaranteed Minimum Income Benefit [Member] | |||||||||||||||||||||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |||||||||||||||||||||
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value | $ 125 | [2] | $ 167 | $ 204 | [2] | $ 357 | $ 466 | $ 559 | |||||||||||||
Guaranteed Minimum Income Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | |||||||||||||||||||||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |||||||||||||||||||||
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value | [4] | $ 125 | $ 204 | ||||||||||||||||||
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