Revenue Recognition (Reconciliation of Accounts Receivable) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers	$ 678	$ 350
Other accounts receivable	30	18
Total accounts receivable	$ 708	$ 368

The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant