INVESTMENT SECURITIES - Securities Classified as Current and Long-Term (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Amortized Cost	$ 10,306	$ 10,641
Gross Unrealized Gains	53	9
Gross Unrealized Losses	(61)	(213)
Fair Value	10,298	10,437
U.S. Treasury and agency obligations
Investment [Line Items]
Amortized Cost	478	419
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(1)	(3)
Fair Value	479	417
U.S. government corporations and agencies, mortgage-backed securities
Investment [Line Items]
Amortized Cost	3,142	2,595
Gross Unrealized Gains	21	3
Gross Unrealized Losses	(22)	(54)
Fair Value	3,141	2,544
Tax-exempt municipal securities
Investment [Line Items]
Amortized Cost	2,096	2,805
Gross Unrealized Gains	12	3
Gross Unrealized Losses	(5)	(37)
Fair Value	2,103	2,771
Residential mortgage-backed securities
Investment [Line Items]
Amortized Cost	84	55
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Fair Value	85	55
Commercial mortgage-backed securities
Investment [Line Items]
Amortized Cost	510	537
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(3)	(14)
Fair Value	509	523
Asset-backed securities
Investment [Line Items]
Amortized Cost	1,037	991
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(6)	(7)
Fair Value	1,032	985
Corporate debt securities
Investment [Line Items]
Amortized Cost	2,959	3,239
Gross Unrealized Gains	14	1
Gross Unrealized Losses	(24)	(98)
Fair Value	$ 2,949	$ 3,142

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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).

+ References

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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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-Publisher FASB
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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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