Schedule II - valuation and qualifying accounts schedule II (Tables)

12 Months Ended

Dec. 31, 2019

SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]

Summary of Valuation Allowance [Table Text Block]

	Beginning Balance		Charged (Credited) to Costs and Expenses		Other		Deductions		Ending Balance
2019:
Allowance for doubtful accounts—accounts and notes receivable(a)	$	—	$	9	$	—	$	—	$	9
Deferred tax asset valuation(a)	213		3		—		—		216
2018:
Allowance for doubtful accounts—accounts and notes receivable(a)	$	2	$	—	$	—	$	(2)	$	—
Deferred tax asset valuation(a)	195		18		—		—		213
Price-risk management credit reserves—liabilities(b)(c)	4		—		(4)		—		—
2017:
Allowance for doubtful accounts—accounts and notes receivable(a)	$	3	$	—	$	—	$	(1)	$	2
Deferred tax asset valuation(a)(d)	151		44		—		—		195
Price-risk management credit reserves—liabilities(b)(c)	5		—		(1)		—		4

 __________

(a) Deducted from related assets.

(b) Deducted from related liabilities.

(c) Included in revenues.

(d) Includes impact of the Tax Cuts and Jobs Act enacted rate reduction.