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INVESTMENT SECURITIES - Securities Classified as Current and Long-Term (Detail) - USD ($) $ in Millions | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Investment [Line Items] |  |
Amortized Cost | $ 10,646 | $ 9,826
Gross Unrealized Gains | 236 | 168
Gross Unrealized Losses | (97) | (196)
Fair Value | 10,785 | 9,798
Debt Securities | Tax-exempt municipal securities |  |
Investment [Line Items] |  |
Amortized Cost | 3,304 | 3,358
Gross Unrealized Gains | 23 | 15
Gross Unrealized Losses | (21) | (68)
Fair Value | 3,306 | 3,305
Debt Securities | Residential Mortgage-Backed Securities |  |
Investment [Line Items] |  |
Amortized Cost | 8 | 9
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 8 | 9
Debt Securities | Commercial Mortgage-Backed Securities |  |
Investment [Line Items] |  |
Amortized Cost | 394 | 307
Gross Unrealized Gains | 2 | 1
Gross Unrealized Losses | (2) | (4)
Fair Value | 394 | 304
Debt Securities | Asset-backed securities |  |
Investment [Line Items] |  |
Amortized Cost | 135 | 160
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 135 | 160
Debt Securities | Corporate debt securities |  |
Investment [Line Items] |  |
Amortized Cost | 4,514 | 3,530
Gross Unrealized Gains | 206 | 145
Gross Unrealized Losses | (40) | (78)
Fair Value | 4,680 | 3,597
Debt Securities | U.S. Treasury and other U.S. government corporations and agencies | U.S. Treasury and agency obligations |  |
Investment [Line Items] |  |
Amortized Cost | 724 | 800
Gross Unrealized Gains | 1 | 1
Gross Unrealized Losses | (9) | (15)
Fair Value | 716 | 786
Debt Securities | U.S. Treasury and other U.S. government corporations and agencies | Mortgage-backed securities |  |
Investment [Line Items] |  |
Amortized Cost | 1,567 | 1,662
Gross Unrealized Gains | 4 | 6
Gross Unrealized Losses | (25) | (31)
Fair Value | $ 1,546 | $ 1,637

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