Leases Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Cost	$ 84	$ 51	$ 231	$ 197
Short-term Lease, Cost	19	24	73	71
Lease, Cost	$ 103	$ 75	304	268
Operating Lease, Payments			222	149
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 244	$ 192
Operating Lease, Weighted Average Remaining Lease Term	7 years		7 years		7 years
Operating Lease, Weighted Average Discount Rate, Percent	4.30%		4.30%		4.60%