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Accounts Receivable, Net	12 Months Ended
Accounts Receivable, Net	Dec. 31, 2019
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable, net consists of freight and other receivables, reduced by an allowance for bill adjustments and uncollectible accounts, based upon expected collectibility. As of December 31, 2019 and 2018, $96 million and $87 million, respectively, of such allowances had been recorded.