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Derivative Instruments (Details) - Interest rate swap contracts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative, Notional Amount	$ 1,600
Not Designated as Hedging Instruments \| Interest expense
Derivative [Line Items]
(Gain) or Loss Recognized on Derivatives	39	$ 4	$ (4)
Other non-current assets \| Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	6
Other current and non-current liabilities \| Not Designated as Hedging Instruments
Derivative [Line Items]
Fair value of interest rate derivative liabilities	47	$ 16
August 2015
Derivative [Line Items]
Derivative, Notional Amount	600
November 2017
Derivative [Line Items]
Derivative, Notional Amount	450
August 2020
Derivative [Line Items]
Derivative, Notional Amount	400
November 2022
Derivative [Line Items]
Derivative, Notional Amount	$ 150