Sales Of Receivables (Summary of Cash Proceeds Received) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net cash received from receivables programs	$ 397	$ (104)
Equipment Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net cash received from receivables programs	121	10
Cash proceeds received	2,874	2,529
Revolving Receivables Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net cash received from receivables programs	276	0
Cash proceeds received	4,174	0
Other Sales of Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net cash received from receivables programs	$ 0	$ (114)