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Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016
Finite-lived intangible assets | $ 18 | $ 16
Indefinite-lived intangible assets | 63 | 59
Intangible Assets, Gross (Excluding Goodwill) | 81 | 75
Accumulated amortization | 9 | 6
Syndicate capacity |  |
Indefinite-lived intangible assets | 47 | 43
Agency force |  |
Indefinite-lived intangible assets | $ 16 | 16
Trade name |  |
Economic useful life measured in years | 8 years |
Finite-lived intangible assets | $ 7 | 6
Accumulated amortization | $ 5 | 3
Distribution channel |  |
Economic useful life measured in years | 15 years |
Finite-lived intangible assets | $ 11 | 10
Accumulated amortization | $ 4 | $ 3

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