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Investments - Valuation changes included in net income for investments (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2018 USD ($)
Debt and Equity Securities, FV-NI [Line Items] |
Total | $ (12)
Equity securities |
Debt and Equity Securities, FV-NI [Line Items] |
Total | (261)
Limited partnership interests |
Debt and Equity Securities, FV-NI [Line Items] |
Total | $ 249

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- Details
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