INVESTMENT SECURITIES - Classified as Current and Long-Term (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Securities Amortized Cost to Fair Value
Amortized Cost	$ 13,440	$ 12,437
Gross Unrealized Gains	218	520
Gross Unrealized Losses	(161)	(6)
Fair Value	13,497	12,951
Common stock	475	815
Total investment securities	13,972	13,766
U.S. Treasury and agency obligations
Debt Securities Amortized Cost to Fair Value
Amortized Cost	611	616
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(10)	(1)
Fair Value	602	616
Mortgage-backed securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	3,265	3,115
Gross Unrealized Gains	33	140
Gross Unrealized Losses	(69)	(1)
Fair Value	3,229	3,254
Tax-exempt municipal securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	810	1,393
Gross Unrealized Gains	33	54
Gross Unrealized Losses	(2)	0
Fair Value	841	1,447
Residential
Debt Securities Amortized Cost to Fair Value
Amortized Cost	373	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(6)	0
Fair Value	367	17
Commercial
Debt Securities Amortized Cost to Fair Value
Amortized Cost	1,394	1,260
Gross Unrealized Gains	27	59
Gross Unrealized Losses	(11)	(1)
Fair Value	1,410	1,318
Asset-backed securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	1,346	1,364
Gross Unrealized Gains	6	10
Gross Unrealized Losses	(4)	(2)
Fair Value	1,348	1,372
Corporate debt securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	5,641	4,672
Gross Unrealized Gains	118	256
Gross Unrealized Losses	(59)	(1)
Fair Value	$ 5,700	$ 4,927

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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