Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 208
Variable Lease, Cost	41
Operating Lease, Payments	208
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 205
Operating Lease, Weighted Average Remaining Lease Term	6 years 2 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	4.00%
Operating Lease, Right-of-Use Asset	$ 699
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Operating Lease, Liability, Current	$ 167
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Operating Lease, Liability, Noncurrent	$ 571
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
2020	$ 197
2021	158
2022	124
2023	92
2024	68
2025 and Thereafter	197
Total Lease Payments	836
Imputed Interest	98
Total Operating Lease Liability	738
Operating Leases, Rent Expense, Net		$ 211	$ 198
Operating Leases, Future Minimum Payments Due [Abstract]
2019		192
2020		158
2021		118
2022		86
2023		58
2024 and Thereafter		177
Operating Leases, Future Minimum Payments Due, Total		$ 789
Lease Residual Value Guarantee [Member]
Lessee, Lease, Description [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 147
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Remaining Lease Term	1 month
Lessee, Operating Lease, Renewal Term	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Remaining Lease Term	30 years
Lessee, Operating Lease, Renewal Term	10 years
Lessee, Operating Lease, Option to Terminate, Term	1 year