Basis of Presentation (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) portfolio_segment class_financing_receivable
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of portfolio segments | portfolio_segment	8
Number of classes of financing receivables | class_financing_receivable	11
Significant Accounting Policies [Line Items]
Risk-based segments, revenue threshold of subcategories	$ 5
Lower Limit | Investor dependent | Growth stage | Mid stage
Significant Accounting Policies [Line Items]
Risk-based segments, revenue threshold of subcategories	5
Lower Limit | Investor dependent | Growth stage | Later stage
Significant Accounting Policies [Line Items]
Risk-based segments, revenue threshold of subcategories	$ 15
Lower Limit | Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO
Significant Accounting Policies [Line Items]
Sponsor equity contribution, percentage of acquisition price	50.00%
Upper Limit | Investor dependent | Growth stage | Mid stage
Significant Accounting Policies [Line Items]
Risk-based segments, revenue threshold of subcategories	$ 15