Debt and Other Financing - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($) shares	Jun. 30, 2022 USD ($) day shares	Jun. 30, 2021 USD ($) shares
Debt Instrument
Increased additional paid-in capital		$ 14,000,000		$ 265,000,000
Convertible Debt
Debt Instrument
Interest expense	$ 7,000,000	7,000,000	$ 13,000,000	12,000,000
Debt discount amortization	$ 2,000,000	2,000,000	$ 4,000,000	4,000,000
2025 Accreting Notes | Convertible Debt
Debt Instrument
Annual coupon rate (in percentage)	2.50%		2.50%
Annual effective interest rate (in percentage)	2.70%		2.70%
Number of trading days (whether or not consecutive) | day			20
Number of trading days (consecutive) | day			30
Debt conversion stock price (in percentage)			276.00%
Principal amount of notes			$ 1,000
Principal amount to be redeemed (in percentage)			100.00%
Debt, fair value	$ 22,000,000		$ 22,000,000
2025 Accreting Notes | Convertible Debt | Class A common stock
Debt Instrument
Increased additional paid-in capital	0	$ 14,000,000	$ 0	265,000,000
2025 Accreting Notes | Convertible Debt | Charlesbank | Class A common stock
Debt Instrument
Debt conversion, principal amount	$ 15,000,000			$ 15,000,000
Debt conversion, converted, shares issued (in shares) | shares		139,196		143,440
Non-Accreting Notes | Convertible Debt
Debt Instrument
Number of trading days (whether or not consecutive) | day			20
Number of trading days (consecutive) | day			30
Debt conversion stock price (in percentage)			130.00%
Convertible debt business period (in days)			5 days
Consecutive debt measurement period (in days)			10 days
Principal amount of notes			$ 1,000
Measurement period, percentage (less than)			98.00%
2022 Notes | Convertible Debt
Debt Instrument
Annual coupon rate (in percentage)	0.375%		0.375%
Annual effective interest rate (in percentage)	0.90%		0.90%
Debt, fair value	$ 2,000,000		$ 2,000,000
2024 Notes | Convertible Debt
Debt Instrument
Annual coupon rate (in percentage)	1.125%		1.125%
Annual effective interest rate (in percentage)	1.50%		1.50%
Debt, fair value	$ 465,000,000		$ 465,000,000
2026 Notes | Convertible Debt
Debt Instrument
Annual coupon rate (in percentage)	1.00%		1.00%
Annual effective interest rate (in percentage)	1.20%		1.20%
Debt, fair value	$ 603,000,000		$ 603,000,000
2025 Notes | Convertible Debt
Debt Instrument
Annual coupon rate (in percentage)	0.625%		0.625%
Annual effective interest rate (in percentage)	0.90%		0.90%
Debt, fair value	$ 1,000,000,000		$ 1,000,000,000
2025 Notes | Convertible Debt | Great Hill | Class A common stock
Debt Instrument
Debt conversion, principal amount				$ 253,000,000
Debt conversion, converted, shares issued (in shares) | shares			3,490,175
Revolving Credit Facility
Debt Instrument
Annual effective interest rate (in percentage)	0.05%		0.05%
Revolving Credit Facility | Senior Secured Revolving Credit Facility
Debt Instrument
Maximum borrowing capacity	$ 600,000,000		$ 600,000,000
Letters of credit outstanding	$ 65,000,000		$ 65,000,000
Debt Instrument, Term			5 years