Impairment Expense (Tables)

6 Months Ended

Jun. 30, 2018

Impairment Expense [Abstract]

Fair Value Measurements, Nonrecurring [Table Text Block]

	Three Months Ended June 30,
	2018				2017
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Long-lived assets	$	69	$	34	$	—	$	—

	Six Months Ended June 30,
	2018				2017
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Long-lived assets	$	69	$	42	$	—	$	4