Goodwill and Intangibles (Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 752	$ 753
Net amortized intangible asset balance	117	116
Acquisitions of amortized intangible assets	0	0
Amortization of intangible assets	17	14	$ 21
Estimated future amortization expense (less than)	20
Trade names and trademarks
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	503	503
Refinery air and operating permits
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 249	$ 250