Sale of Accounts Receivable: (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Sale of Accounts Receivable [Abstract]
Accounts receivable sold	$ 11,900	$ 11,800
Trade receivables sold and derecognized that remain uncollected	1,000	900	$ 1,200
Gain (loss) on sale of accounts receivable	$ 26	$ 9	$ 9