Schedule of Valuation and Qualifying Accounts Disclosure (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		$ 9	$ 9	$ 6
Charged to Expense		(6)	(5)	(4)
Charged to Other Accounts		(1)	1	2
Deductions	[1]	(5)	(6)	(3)
Balance at End of Year		9	9	9
Deferred Tax Asset Valuation Allowance [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		1,000	1,168	1,581
Charged to Expense		(127)	(168)	(413)
Charged to Other Accounts		0	0	0
Deductions	[1]	0	0	0
Balance at End of Year		$ 873	$ 1,000	$ 1,168

[1] Represents write-offs of accounts considered to be uncollectible and previously reserved.