Fair Value of Financial Instruments - Quantitative Information About Significant Unobservable Inputs (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Equity warrant assets (public portfolio) | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value		$ 2
Equity warrant assets (public portfolio) | Volatility | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.278
Equity warrant assets (public portfolio) | Volatility | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.550
Equity warrant assets (public portfolio) | Volatility | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.437
Equity warrant assets (public portfolio) | Risk-Free Interest Rate | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.006
Equity warrant assets (public portfolio) | Risk-Free Interest Rate | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.015
Equity warrant assets (public portfolio) | Risk-Free Interest Rate | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.011
Equity warrant assets (public portfolio) | Sales restrictions discount | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.10	0.100
Equity warrant assets (public portfolio) | Sales restrictions discount | Upper Limit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.20
Equity warrant assets (public portfolio) | Sales restrictions discount | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.20	0.200
Equity warrant assets (public portfolio) | Sales restrictions discount | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average		0.107
Equity warrant assets (private portfolio) | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 377	$ 267
Equity warrant assets (private portfolio) | Volatility | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.232	0.247
Equity warrant assets (private portfolio) | Volatility | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.487	0.550
Equity warrant assets (private portfolio) | Volatility | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.412	0.430
Equity warrant assets (private portfolio) | Risk-Free Interest Rate | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.034	0.0006
Equity warrant assets (private portfolio) | Risk-Free Interest Rate | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.048	0.014
Equity warrant assets (private portfolio) | Risk-Free Interest Rate | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.043	0.008
Equity warrant assets (private portfolio) | Marketability discount | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.165	20.1
Equity warrant assets (private portfolio) | Marketability discount | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.165	0.201
Equity warrant assets (private portfolio) | Remaining life assumption | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.400	40
Equity warrant assets (private portfolio) | Remaining life assumption | Weighted average | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted Average	0.400	0.400
Contingent conversion rights | Private Portfolio | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 12