Commitments and Contingencies (Unaudited) (Details) £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020 GBP (£) Rate	Mar. 31, 2020 USD ($) Rate	Dec. 31, 2019 USD ($)
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		$ 533	$ 531
Loss Contingency, Range of Possible Loss, Portion Not Accrued		448	448
Recorded Third-Party Environmental Recoveries, Amount		439	$ 436
Financial Arrangements
Standby Unused Letters Of Credit and bank guarantees		469
Surety Bond Outstanding		182
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Compliance	the company was in compliance with all covenants under its credit agreements.
Two Year Term [Member] [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	£ 120	149
Line of Credit Outstanding	£ 55	68
Five Year Term [Member] [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,000
Line of Credit Outstanding		0
London Interbank Offered Rate (LIBOR) [Member] | Two Year Term [Member] [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period | Rate	1.10%
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Commercial Paper, Maximum Borrowing Capacity		2,000
Commercial Paper		$ 744
Commercial Paper, Weighted Average Interest Rate | Rate	1.88%	1.88%
Commercial Paper, Term	3 months
Other Current Liabilities [Member]
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		$ 163
Other Noncurrent Liabilities [Member]
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		370
Other Current Assets [Member]
Site Contingency [Line Items]
Recorded Third-Party Environmental Recoveries, Amount		131
Other Noncurrent Assets [Member]
Site Contingency [Line Items]
Recorded Third-Party Environmental Recoveries, Amount		$ 308