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Accounts Receivable, Net	12 Months Ended
Accounts Receivable, Net	Dec. 31, 2021
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable, net consists of freight and other receivables, reduced by an allowance for credit losses which is based upon expected collectibility. As of December 31, 2021 and 2020, $40 million and $54 million, respectively, of such allowances had been recorded.