Leases Total Lease Cost (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease cost	$ 320	$ 318
Variable lease cost	28	11
Short-term lease cost	93	75
Total lease cost	$ 441	$ 404
Operating Leases, Rent Expense Under ASC 840			$ 375