Impairments (Tables)

9 Months Ended

Sep. 30, 2017

Asset Impairment Charges [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset

A summary of our impairments of fixed assets by asset class and other charges for the Current Quarter, the Prior Quarter, the Current Period and the Prior Period is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
	($ in millions)
Barnett Shale exit costs	$	—	$	616	$	—	$	616
Gathering systems	—		96		—		96
Natural gas compressors	—		32		—		52
Buildings and land	1		7		3		14
Other	8		—		423		17
Total impairments of fixed assets and other	$	9	$	751	$	426	$	795