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Debt (Principal Payments For Investment Agreements, MTNs and VIE Obligations) (Detail) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017
Debt Instrument [Line Items] |  |  |
2022 |  | $ 265.0 |
2023 |  | 0.0 |
Thereafter |  | 1,248.0 |
Total |  | 1,513.0 |
Accrued interest |  | 751.0 | $ 624.0
Investment Agreement Obligations [Member] |  |  |
Debt Instrument [Line Items] |  |  |
2019 |  | 7.0 |
2020 |  | 35.0 |
2021 |  | 2.0 |
2022 |  | 2.0 |
2023 |  | 20.0 |
Thereafter |  | 295.0 |
Total expected principal payments | [1] | 361.0 |
Less discount and other adjustments | [2] | 50.0 |
Total |  | 311.0 |
Accrued interest |  | 5.0 |
Carrying amount adjustment |  | $ 4.0 |
Latest maturity year |  | 2037 |
Medium Term Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
2019 |  | $ 58.0 |
2020 |  | 0.0 |
2021 |  | 0.0 |
2022 |  | 58.0 |
2023 |  | 0.0 |
Thereafter |  | 835.0 |
Total expected principal payments | [3] | 951.0 |
Less discount and other adjustments | [4] | 229.0 |
Total |  | 722.0 |
Accrued interest |  | 5.0 |
Carrying amount adjustment |  | $ 34.0 |
Latest maturity year |  | 2036 |
Variable Interest Entity Debt [Member] | International And Structured Finance Insurance [Member] |  |  |
Debt Instrument [Line Items] |  |  |
2019 |  | $ 108.0 |
2020 |  | 396.0 |
2021 |  | 72.0 |
2022 |  | 41.0 |
2023 |  | 13.0 |
Thereafter |  | 1,111.0 |
Total expected principal payments | [5] | 1,741.0 |
Net fair value |  | $ 480.0 |
Latest maturity year |  | 2052 |
[1] | Amounts reflect principal due at maturity for investment agreements issued at a discount.
[2] | Discount is net of carrying amount adjustment of $4 million and accrued interest adjustment of $5 million.
[3] | Amounts reflect principal due at maturity for notes issued at a discount.
[4] | Discount is net of carrying amount adjustment of $34 million and accrued interest adjustment of $5 million.
[5] | Includes $480 million of VIE notes accounted for at fair value as of December 31, 2018.

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