Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2019

Schedule II

Valuation and Qualifying Accounts

For the Years Ended December 31, 2019, 2018 and 2017



(In millions) Description	Balance at Beginning of Period		Additions Charged to Costs and Expenses		Deductions		Other		Balance at End of Period
Allowance for doubtful accounts:
2019	$	8	$	17	$	16	$	—	$	9
2018	7		17		16		—		8
2017	10		20		23		—		7
Obsolescence allowance—spare parts:
2019	$	412	$	76	$	63	$	—	$	425
2018	354		73		15		—		412
2017	295		75		17		1		354
Valuation allowance for deferred tax assets:
2019	$	59	$	—	$	1	$	—	$	58
2018	63		2		6		—		59
2017	68		11		27		11		63