Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Provisional net benefit related to U.S. 2017 Tax Reform, estimated impact	$ 151	$ 12
Estimated write-down of net deferred tax liabilities		$ 7	$ 334	$ 0
U.S. statutory tax rate (as a percent)		21.00%	35.00%	35.00%
Estimated cost of a mandatory deemed repatriation of non-U.S. earnings		$ (5)	$ 183	$ 0
Reconciliation of statutory rate to effective income tax rate
Taxes computed at U.S. statutory rates		$ 91	$ 206	$ 196
U.S. statutory tax rate (as a percent)		21.00%	35.00%	35.00%
(Decreases) increases in taxes resulting from:
State Income Tax, net of Federal Tax		$ 1	$ 2	$ 2
State Income Tax, net of Federal Tax (as a percent)		0.20%	0.30%	0.40%
Subsidiaries' results subject to tax rates other than U.S. statutory rates		$ 28	$ (31)	$ (36)
Subsidiaries' results subject to tax rates other than U.S. statutory rates (as a percent)		6.50%	(5.30%)	(6.50%)
Income from non-U.S. subsidiaries taxed at U.S. statutory rates, net of foreign tax credits		$ 0	$ (16)	$ 2
Income from non-U.S. subsidiaries taxed at U.S. statutory rates, net of foreign tax credits (as a percent)		0.00%	(2.70%)	0.30%
Foreign currency translation taxed at non-U.S. subsidiaries		$ (1)	$ (12)	$ 13
Foreign currency translation taxed at non-U.S subsidiaries (as a percent)		(0.20%)	(2.00%)	2.30%
U.S. deferred tax rate change		$ (7)	$ (334)	$ 0
U.S. deferrd tax rate change (as a percent)		(1.60%)	(56.60%)	0.00%
Mandatory deemed repatriation of non-U.S. earnings		$ (5)	$ 183	$ 0
Mandatory deemed repatriation of non-U.S. earnings (as a percent)		(1.20%)	31.00%	0.00%
Prior year tax adjustments		$ 11	$ 0	$ 0
Prior year tax adjustments (as a percent)		2.50%	0.00%	0.00%
Valuation allowances		$ (7)	$ 0	$ 0
Valuation allowances (as a percent)		(1.60%)	0.00%	0.00%
Other, net		$ (3)	$ (2)	$ (6)
Other, net (as a percent)		(0.70%)	(0.40%)	(1.10%)
Provision (benefit) for income taxes		$ 108	$ (4)	$ 171
Provision (benefit) for income taxes, Effective Income Tax Rate (as a percent)		24.90%	(0.70%)	30.40%
Prior year tax adjustments		$ 11	$ 0	$ 0
Valuation allowances		$ 7	$ 0	$ 0