Income Taxes (Income Tax Payables and Income Tax Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income taxes receivable—current	$ 131	$ 163
Income Taxes Receivable, Noncurrent	10	8
Total income taxes receivable	141	171
Income taxes payable—current	172	210
Income taxes payable—noncurrent	0	7
Total income taxes payable	$ 172	$ 217