Fair Value of Financial Instruments - Quantitative Information About Significant Unobservable Inputs (Details) - Level 3 $ in Millions	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Equity warrant assets | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 2
Equity warrant assets | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value	$ 318	$ 267
Contingent conversion rights | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value	$ 6
Volatility | Equity warrant assets | Lower Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.278
Volatility | Equity warrant assets | Lower Limit | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.240	0.247
Volatility | Equity warrant assets | Upper Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.550
Volatility | Equity warrant assets | Upper Limit | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.523	0.550
Volatility | Equity warrant assets | Weighted Average | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.011
Volatility | Equity warrant assets | Weighted Average | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.427	0.430
Risk-Free interest rate | Equity warrant assets | Lower Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.006
Risk-Free interest rate | Equity warrant assets | Lower Limit | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.017	0.0006
Risk-Free interest rate | Equity warrant assets | Upper Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.015
Risk-Free interest rate | Equity warrant assets | Upper Limit | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.030	0.0140
Risk-Free interest rate | Equity warrant assets | Weighted Average | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.107
Risk-Free interest rate | Equity warrant assets | Weighted Average | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.028	0.008
Sales restrictions discount | Equity warrant assets | Lower Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.100
Sales restrictions discount | Equity warrant assets | Upper Limit | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.200
Sales restrictions discount | Equity warrant assets | Weighted Average | Public Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input		0.437
Marketability discount | Equity warrant assets | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.182	0.201
Marketability discount | Equity warrant assets | Weighted Average | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.182	0.201
Remaining life assumption | Equity warrant assets | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.400	0.400
Remaining life assumption | Equity warrant assets | Weighted Average | Private Portfolio
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Measurement input	0.400	0.400