SHAREHOLDERS' EQUITY - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	$ 2,632	$ 2,936	$ 2,630	$ 625
Other comprehensive income loss before reclassifications net of tax	[1]	765	2,488	755	4,849
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	4	8	16	(42)
Other comprehensive income (loss), net of tax	[1]	769	2,496	771	4,807
Balance, end of period	[1]	3,401	5,432	3,401	5,432
Unrealized foreign currency translation gains (losses)
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(1,650)	(1,584)	(1,983)	(2,196)
Other comprehensive income loss before reclassifications net of tax	[1]	70	737	403	1,349
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	0	0	0	0
Other comprehensive income (loss), net of tax	[1]	70	737	403	1,349
Balance, end of period	[1]	(1,580)	(847)	(1,580)	(847)
Unrealized gains (losses) on investment securities
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	4,474	4,684	4,805	2,986
Other comprehensive income loss before reclassifications net of tax	[1]	698	1,750	357	3,498
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	1	7	11	(43)
Other comprehensive income (loss), net of tax	[1]	699	1,757	368	3,455
Balance, end of period	[1]	5,173	6,441	5,173	6,441
Unrealized gains (losses) on derivatives
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(22)	(24)	(24)	(26)
Other comprehensive income loss before reclassifications net of tax	[1]	(1)	5	1	7
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	0	0	0	0
Other comprehensive income (loss), net of tax	[1]	(1)	5	1	7
Balance, end of period	[1]	(23)	(19)	(23)	(19)
Pension liability adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(170)	(140)	(168)	(139)
Other comprehensive income loss before reclassifications net of tax	[1]	(2)	(4)	(6)	(5)
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	3	1	5	1
Other comprehensive income (loss), net of tax	[1]	1	(3)	(1)	(4)
Balance, end of period	[1]	$ (169)	$ (143)	$ (169)	$ (143)

[1] All amounts in the table above are net of tax.