Derivative Financial Instruments (Derivative Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ 34	$ (292)	$ (100)
Commodity price derivatives | Derivative gain (loss), net
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	34	(292)	(99)
Interest rate derivatives | Derivative gain (loss), net
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	0	0	(1)
Contingent consideration | Interest and other income
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	$ (45)	$ 0	$ 0