Revenue Recognition (Allowance for Doubtful Accounts Rollforward) (Details) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 147	$ 117	$ 134	$ 112
Charged to costs and expenses	4	3	9	6
Charged to revenue	16	11	37	28
Deductions	(9)	(8)	(22)	(23)
Ending balance	$ 158	$ 123	$ 158	$ 123