INVESTMENT SECURITIES - Securities Classified as Current and Long-Term (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investment [Line Items]
Amortized Cost	$ 10,073	$ 12,104
Gross Unrealized Gains	6	286
Gross Unrealized Losses	(236)	(88)
Fair Value	9,843	12,302
Tax-exempt municipal securities
Investment [Line Items]
Amortized Cost	3,045	3,884
Gross Unrealized Gains	3	33
Gross Unrealized Losses	(49)	(28)
Fair Value	2,999	3,889
Residential mortgage-backed securities
Investment [Line Items]
Amortized Cost	17	26
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	17	26
Commercial mortgage-backed securities
Investment [Line Items]
Amortized Cost	533	455
Gross Unrealized Gains	0	3
Gross Unrealized Losses	(16)	(2)
Fair Value	517	456
Asset-backed securities
Investment [Line Items]
Amortized Cost	574	407
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(2)	0
Fair Value	573	408
Corporate debt securities
Investment [Line Items]
Amortized Cost	2,946	5,175
Gross Unrealized Gains	2	244
Gross Unrealized Losses	(96)	(37)
Fair Value	2,852	5,382
U.S. Treasury and other U.S. government corporations and agencies \| U.S. Treasury and agency obligations
Investment [Line Items]
Amortized Cost	631	532
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(4)	(2)
Fair Value	627	531
U.S. Treasury and other U.S. government corporations and agencies \| Mortgage-backed securities
Investment [Line Items]
Amortized Cost	2,327	1,625
Gross Unrealized Gains	0	4
Gross Unrealized Losses	(69)	(19)
Fair Value	$ 2,258	$ 1,610

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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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