ASC 606 Adoption And Revenue Recognition (Changes In Contract Assets And Contract Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Jan. 01, 2018
ASC 606 Adoption And Revenue Recognition [Abstract]
Contract assets, Beginning balance	$ 77
Revenue recognized included in opening contract balance	(57)
Credits granted, excluding amounts recognized as revenue	49
Contract assets, Ending balance	69
Contract liabilities, Beginning balance	(60)
Revenue recognized included in opening contract balance	119
Cash received, excluding amounts recognized as revenue	(135)
Other	5
Contract liabilities, Ending balance	(71)
Short-term contract assets	44	$ 40
Long-term contract assets	25	37
Short-term contract liabilities	49	41
Long-term contract liabilities	$ 22	$ 19

Contrac With Customer Asset Contract Asset Initiation

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- Definition

Contract With Customer Liability Cash Received Excluding Amounts Recognized As Revenue

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Contract With Customer, Liability, Other

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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