Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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Nominal or face amount used to calculate payment on derivative.

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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The net gain (loss) relating to components of the gain (loss) on the cash flow hedging instrument excluded from the assessment of cash flow hedge effectiveness. Recognized in earnings.

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Investments - Derivative Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative contract term			3 months
Fair Value
Net liability position of derivatives that contain certain credit risk-related contingent features
Gain (Loss) Recognized in Income Statement
Gain (Loss) Recognized in Other Comprehensive Income
Gains (losses) reclassified from other comprehensive income into shareholders' net income
Amounts excluded from assessment of hedge effectiveness
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Foreign Currency Swaps [Member]
Derivative [Line Items]
Notional amount	763		763		525
Designated as Hedging Instrument [Member] \| Net Investment Hedge [Member] \| Foreign Currency Swaps [Member]
Derivative [Line Items]
Notional amount	439		439		439
Non designated [Member] \| Forward Contracts [Member]
Derivative [Line Items]
Notional amount	$ 407		$ 407		$ 309