Leases - Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating lease cost	$ 124
Short-term lease cost	34
Variable lease cost	62
Total lease cost	$ 220
Operating Leases, Rent Expense, Net		$ 161	$ 169