INVESTMENT SECURITIES - Schedule of Investment Securities Classified as Current and Long-Term (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Investment [Line Items]
Amortized Cost	$ 9,246	$ 9,018
Gross Unrealized Gains	381	218
Gross Unrealized Losses	(25)	(126)
Fair Value	9,602	9,110
Debt Securities \| Tax-exempt municipal securities
Investment [Line Items]
Amortized Cost	3,157	2,611
Gross Unrealized Gains	73	61
Gross Unrealized Losses	(4)	(4)
Fair Value	3,226	2,668
Debt Securities \| Residential Mortgage-Backed Securities
Investment [Line Items]
Amortized Cost	10	13
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	10	13
Debt Securities \| Commercial Mortgage-Backed Securities
Investment [Line Items]
Amortized Cost	498	1,024
Gross Unrealized Gains	13	2
Gross Unrealized Losses	(8)	(41)
Fair Value	503	985
Debt Securities \| Asset-backed securities
Investment [Line Items]
Amortized Cost	187	264
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	(2)
Fair Value	188	263
Debt Securities \| Corporate debt securities
Investment [Line Items]
Amortized Cost	3,223	2,873
Gross Unrealized Gains	268	140
Gross Unrealized Losses	(12)	(55)
Fair Value	3,479	2,958
Debt Securities \| U.S. Treasury and other U.S. government corporations and agencies: \| U.S. Treasury and agency obligations
Investment [Line Items]
Amortized Cost	659	331
Gross Unrealized Gains	2	2
Gross Unrealized Losses	0	(1)
Fair Value	661	332
Debt Securities \| U.S. Treasury and other U.S. government corporations and agencies: \| Mortgage-backed securities
Investment [Line Items]
Amortized Cost	1,512	1,902
Gross Unrealized Gains	24	12
Gross Unrealized Losses	(1)	(23)
Fair Value	$ 1,535	$ 1,891

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
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