INVESTMENTS AND FAIR VALUE MEASUREMENT - SUMMARY OF CRYPTO ASSETS HELD IN CUSTODY (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total user cryptocurrencies safeguarding obligation and corresponding asset	$ 8,593	$ 0	$ 0
Dogecoin (DOGE)
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total user cryptocurrencies safeguarding obligation and corresponding asset	2,845
Bitcoin (BTC)
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total user cryptocurrencies safeguarding obligation and corresponding asset	2,722
Ethereum (ETH)
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total user cryptocurrencies safeguarding obligation and corresponding asset	2,173
Other
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total user cryptocurrencies safeguarding obligation and corresponding asset	$ 853