INVESTMENT SECURITIES - Classified as Current and Long-Term (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Securities Amortized Cost to Fair Value
Amortized Cost	$ 18,302	$ 15,946
Gross Unrealized Gains	34	9
Gross Unrealized Losses	(1,328)	(1,701)
Fair Value	17,008	14,254
Common stock	0	7
Total investment securities	17,008	14,261
U.S. Treasury and agency obligations
Debt Securities Amortized Cost to Fair Value
Amortized Cost	2,717	1,093
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(51)	(55)
Fair Value	2,667	1,039
Mortgage-backed securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	3,946	3,697
Gross Unrealized Gains	1	4
Gross Unrealized Losses	(425)	(471)
Fair Value	3,522	3,230
Tax-exempt municipal securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	879	765
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(22)	(37)
Fair Value	858	728
Residential
Debt Securities Amortized Cost to Fair Value
Amortized Cost	465	477
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(66)	(76)
Fair Value	400	401
Commercial
Debt Securities Amortized Cost to Fair Value
Amortized Cost	1,471	1,554
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(126)	(155)
Fair Value	1,345	1,399
Asset-backed securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	1,813	1,809
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(44)	(79)
Fair Value	1,771	1,731
Corporate debt securities
Debt Securities Amortized Cost to Fair Value
Amortized Cost	7,011	6,551
Gross Unrealized Gains	28	3
Gross Unrealized Losses	(594)	(828)
Fair Value	$ 6,445	$ 5,726

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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Amortized cost 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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