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Investment Information - Investments in operating affiliates (Details) € / shares in Units, $ / shares in Units, € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2021 EUR (€) € / shares
Schedule of Equity Method Investments [Line Items]
Investment in operating affiliates	$ 1,313	$ 1,240
Income (loss) from operating affiliates	$ 180	200	$ 184
Coface
Schedule of Equity Method Investments [Line Items]
Percentage ownership	29.90%			29.50%	29.50%
Investment in affiliate, price per share | € / shares					€ 9.95
Equity method investment, aggregate cost				$ 546	€ 453
Investment in operating affiliates	$ 707	$ 592
Coface | Issued Shares Excluding Treasury Stock
Schedule of Equity Method Investments [Line Items]
Percentage ownership	30.00%
Greysbridge Holdings Ltd
Schedule of Equity Method Investments [Line Items]
Percentage ownership	30.00%	40.00%
Investment in affiliate, price per share | $ / shares				$ 35.00
Investment in operating affiliates	$ 486	$ 523

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