Leases Leases - Lease Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	7 years 7 months 21 days
Variable Lease, Cost	$ 623
Operating Lease, Cost	170
Finance Lease, Right-of-Use Asset, Amortization	16
Finance Lease, Interest Expense	41
Short-term Lease, Cost	7
Lease, Cost	$ 857
Operating Lease, Weighted Average Discount Rate, Percent	5.20%
Finance Lease, Weighted Average Discount Rate, Percent	8.60%
Finance Lease, Weighted Average Remaining Lease Term	28 years 10 months 2 days