Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
State and foreign withholding taxes not accrued	$ 1,800,000,000
Effective tax rate	27.30%	25.60%	42.90%
Provisional charge			$ 240,000,000
Charge related to change in tax rate			220,000,000
Impact of adjustment to estimate tax expense		$ (5,000,000)
Net increases in valuation allowances	$ 60,000,000	36,000,000
Increase in income tax expense		1,000,000
Net operating loss carryforwards (as a percent)	69.00%
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits	$ 75,000,000	64,000,000	56,000,000
Accrued interest and penalties, before any applicable federal benefit	31,000,000	$ 15,000,000	$ 12,000,000
Minimum
Tax Credit Carryforward [Line Items]
Reasonably possible decrease in unrecognized tax benefits	0
Maximum
Tax Credit Carryforward [Line Items]
Reasonably possible decrease in unrecognized tax benefits	10,000,000
Federal
Tax Credit Carryforward [Line Items]
Operating loss carryforwards tax benefits	32,000,000
State and Local
Tax Credit Carryforward [Line Items]
Operating loss carryforwards tax benefits	34,000,000
Non-U.S.
Tax Credit Carryforward [Line Items]
Operating loss carryforwards tax benefits	$ 84,000,000