Commitments and Contingencies (Details) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2025 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Loss Contingencies [Line Items]
Funded loans unpaid principal	$ 48,400	$ 48,400
Letters of credit outstanding	347	347
Accrued loan loss	68	68	$ 63
Assets available for recourse	1,600	1,600
Guarantees total	189	189
Recognized revenue included in contract liability	(58)	(206)
Deferred and contingent consideration		(105)	(93)
Indirect tax liabilities primarily related to sales and use tax	94	94	91
Commitments to investment in future real estate investment	187	$ 187
Commitments to investment in future real estate investment (as a percent)		0.50
Commitment to investment in consolidated projects	357	$ 357
Commitments to investment in unconsolidated real estate subsidiary	62	62
Accounts Payable, Accrued Expenses and Long-term Deferred and Contingent Consideration
Loss Contingencies [Line Items]
Recognized revenue included in contract liability		(234)	199
Performance Guarantee
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	968	968	808
Warehouse Receivable
Loss Contingencies [Line Items]
Warehouse receivables	972	972
Funded Loan Subject to Loss Sharing Arrangements
Loss Contingencies [Line Items]
Funded loans unpaid principal	45,300	45,300
Letters of credit outstanding	165	165	160
SBL Program
Loss Contingencies [Line Items]
Letters of credit outstanding	$ 5	$ 5	$ 5
Percentage of maximum original principal amount loan loss	10.00%	10.00%
Funded Loan Not Subject to Loss Sharing Arrangements
Loss Contingencies [Line Items]
Letters of credit outstanding	$ 170	$ 170

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