Commitments and Contingencies (Unaudited) (Details) £ in Millions	3 Months Ended
	Mar. 31, 2019 GBP (£) Rate	Mar. 31, 2019 USD ($) Rate	Dec. 31, 2018 USD ($)
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		$ 473,000,000	$ 461,000,000
Recorded Third-Party Environmental Recoveries, Amount		353,000,000	343,000,000
Financial Arrangements
Standby Unused Letters Of Credit and bank guarantees		493,000,000
Surety Bond Outstanding		200,000,000
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Compliance	the company was in compliance with all covenants under its credit agreements.
Short Term Debt, Maximum Borrowing Capacity		2,000,000,000
Commercial Paper		$ 1,000,000,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time | Rate	3.04%	3.04%
Debt Instrument, Term	3 months
Two Year Term [Member] [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	£ 120	$ 156,000,000
Line of Credit Outstanding	£ 70	91,000,000
Five Year Term [Member] [Domain]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,000,000,000
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%
Other Current Liabilities [Member]
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		172,000,000
Other Noncurrent Liabilities [Member]
Site Contingency [Line Items]
Accrual for Environmental Remediation Costs		301,000,000
Other Current Assets [Member]
Site Contingency [Line Items]
Recorded Third-Party Environmental Recoveries, Amount		139,000,000
Other Noncurrent Assets [Member]
Site Contingency [Line Items]
Recorded Third-Party Environmental Recoveries, Amount		214,000,000
Environmental Issue [Member] | Maximum
Site Contingency [Line Items]
Loss Contingency, Estimate of Possible Loss		836,000,000	835,000,000
Environmental Issue [Member] | Minimum
Site Contingency [Line Items]
Loss Contingency, Estimate of Possible Loss		$ 460,000,000	$ 447,000,000