Financing Receivables - By Portfolio Segment (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2025 USD ($) class	Dec. 31, 2024 USD ($) class
Financing receivables
Amortized cost	$ 12,289	$ 12,639
Allowance for credit losses:
Allowance for credit losses, beginning balance	128
Allowance for credit losses, ending balance	$ 130	$ 128
Client Financing Receivables
Financing receivables
Number of classes of financing receivable | class	3	3
Amortized cost	$ 11,065	$ 10,418
Allowance for credit losses:
Allowance for credit losses, beginning balance	123	150
Write-offs	(19)	(3)
Recoveries	0	1
Additions/(releases)	10	(12)
Other	12	(14)
Allowance for credit losses, ending balance	125	123
Client Financing Receivables | Americas
Financing receivables
Amortized cost	6,306	5,861
Allowance for credit losses:
Allowance for credit losses, beginning balance	69	92
Write-offs	(14)	(2)
Recoveries	0	1
Additions/(releases)	7	(10)
Other	6	(11)
Allowance for credit losses, ending balance	68	69
Client Financing Receivables | Europe/Middle East/Africa
Financing receivables
Amortized cost	3,347	3,128
Allowance for credit losses:
Allowance for credit losses, beginning balance	45	48
Write-offs	0	(1)
Recoveries	0	0
Additions/(releases)	0	0
Other	6	(2)
Allowance for credit losses, ending balance	51	45
Client Financing Receivables | Asia Pacific
Financing receivables
Amortized cost	1,412	1,429
Allowance for credit losses:
Allowance for credit losses, beginning balance	9	11
Write-offs	(5)	0
Recoveries	0	0
Additions/(releases)	2	(2)
Other	0	0
Allowance for credit losses, ending balance	$ 7	$ 9