INVESTMENT SECURITIES - Securities Classified as Current and Long-Term (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	$ 14,040	$ 13,440
Gross Unrealized Gains	20	218
Gross Unrealized Losses	(760)	(161)
Fair Value	13,300	13,497
Common stock	184	475
Total investment securities	13,484	13,972
U.S. Treasury and agency obligations
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	621	611
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(33)	(10)
Fair Value	588	602
Mortgage-backed securities
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	3,326	3,265
Gross Unrealized Gains	2	33
Gross Unrealized Losses	(256)	(69)
Fair Value	3,072	3,229
Tax-exempt municipal securities
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	796	810
Gross Unrealized Gains	3	33
Gross Unrealized Losses	(18)	(2)
Fair Value	781	841
Residential
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	480	373
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(30)	(6)
Fair Value	450	367
Commercial
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	1,570	1,394
Gross Unrealized Gains	1	27
Gross Unrealized Losses	(58)	(11)
Fair Value	1,513	1,410
Asset-backed securities
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	1,579	1,346
Gross Unrealized Gains	2	6
Gross Unrealized Losses	(18)	(4)
Fair Value	1,563	1,348
Corporate debt securities
Investment Securities, Available-for-sale Amortized Cost to Fair Value
Amortized Cost	5,668	5,641
Gross Unrealized Gains	12	118
Gross Unrealized Losses	(347)	(59)
Fair Value	$ 5,333	$ 5,700

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

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