Other Noncurrent Liabilities and Deferred Credits (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Environmental remediation (U)	$ 185	$ 253
Income taxes (H)	146	162
Accrued compensation and retirement costs	195	218
Sale-leaseback financing obligation	119	0
Other	94	126
Other noncurrent liabilities and deferred credits	$ 739	$ 759

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer.

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Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all domestic and foreign income tax obligations due beyond one year or the operating cycle, whichever is longer. Alternate captions include income taxes payable, noncurrent.

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The liability due as of the balance sheet date for leasebacks accounted for using the deposit method.

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