Background and Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) reporting_unit segment numberOfSegment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jan. 01, 2021 USD ($)
Description of Business
Number of reportable segments | numberOfSegment	1
Bank overdrafts	$ 0	$ 0
Accounts receivable, period past due	30 days
Number of reporting units | reporting_unit	1
Number of operating segments | segment	1
Assets	$ 17,253	19,759
Accounts receivable	545	517
Member's equity	3,644	7,119
Income tax expense (benefit)	$ (2)	256	$ 197
Correction Of Error From Understatement Of Revenues And Network Expenses Prior To 2021
Description of Business
Assets		23
Accounts receivable		$ 23
Member's equity				$ 23
Capitalized software
Description of Business
Finite-lived intangible assets, useful life	7 years
Other
Description of Business
Finite-lived intangible assets, useful life	5 years
Minimum
Description of Business
Contract term	1 year
Minimum | Customer relationships
Description of Business
Finite-lived intangible assets, useful life	7 years
Maximum
Description of Business
Contract term	5 years
Period company may receive up front payments for services to be provided in the future (in years)	20 years
Maximum | Customer relationships
Description of Business
Finite-lived intangible assets, useful life	14 years
Weighted Average | Consumer Customers
Description of Business
Length of customer life	35 months