Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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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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No definition available.

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Derivatives and Risk Management (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Commodities
Derivative [Line Items]
Derivative assets	$ 150
Interest rate swaps
Derivative [Line Items]
Derivative assets		$ 1
Derivative liabilities	1
Not Designated as Hedging Instrument \| Interest rate swaps
Derivative [Line Items]
Notional amount	$ 170