Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	20.80%	25.00%
Cash paid for income taxes, net of refunds	$ 88	$ 37
Provisional estimate of the benefit of the 2017 tax act due to the one-time transition tax	5
Provisional estimate of the impact of the 2017 tax act due to deemed repatriation transition tax	740
Tax expense relating to remitted accumulated earnings of non-U.S. subsidiaries	$ 27