Leases Lease Balance Sheet (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 281
Finance Lease, Right-of-Use Asset	57
Lease Right of Use Assets	338
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	19
Operating Lease, Liability	90
Finance Lease, Liability, Current	7
Operating Lease, Liability, Noncurrent	212
Finance Lease, Liability, Noncurrent	66
Lease Liabilities	$ 375