Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment	$ 269		$ 257
Exchange traded equity securities	22		19
Gain (loss) on equity securities	3	$ 2
Equity investments without readily determinable market value	17		16
Private Equity Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment	195		182
Equity method investment income (loss)	2	$ 1
Commitments for potential future investments	105
Private Insurance and Consulting
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment	$ 74		$ 75
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)	2 years	2 years
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)	4 years	4 years

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Commitments for Potential Future Investments

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Amount of investment in equity security without readily determinable fair value.

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