SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance, increase (decrease)			$ (68)
Tax Cuts and Jobs Act of 2017, change in deferred tax asset valuation allowance	$ 32	$ 1,100	244	$ 1,100
Tax Cuts and Jobs Act of 2017, Tax Credit Carryforwards, Alternative Minimum Tax				371
Valuation allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year			4,575	6,058	$ 4,183
Other Additions (Deductions)			(345)	(1,484)	1,852
Additons Charged to Other Accounts			8	1	23
SEC Schedule, 12-09, Valuation Allowances and Reserves, Period Increase (Decrease)			269
Balance at End of Year	4,507	4,575	4,507	4,575	6,058
Reserve for Taxes, Other than Income Taxes [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year			58	64	83
Other Additions (Deductions)			7	(2)	13
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction			(1)		(3)
SEC Schedule, 12-09, Valuation Allowance and Reserves, Deduction, Other			(2)	(4)	(29)
Balance at End of Year	$ 62	$ 58	62	$ 58	$ 64
Foreign Tax Credits
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance, increase (decrease)			(305)
Net Operating Losses
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance, increase (decrease)			$ (54)