Revenue from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2025 |
Sep. 30, 2024 |
Dec. 31, 2023 |
Sep. 30, 2025 |
Sep. 30, 2024 |
Dec. 31, 2024 |
|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||||||
| Allowance for doubtful accounts | $ 11 | $ 11 | $ 10 | |||
| Corporate | Adenza Holdings, Inc., | ||||||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||||||
| Reduction in revenue | $ 32 | $ 34 | $ (2) | |||
| Market Services | Market Services Segment | Services transferred at a point in time | ||||||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||||||
| Revenue recognized (as a percentage) | 95.30% | 94.60% | 95.20% | 95.40% | ||
| Market Services | Market Services Segment | Services transferred over time | ||||||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||||||
| Revenue recognized (as a percentage) | 4.70% | 5.40% | 4.80% | 4.60% | ||