NOTES PAYABLE - Summary of Notes Payable (Parenthetical) (Details) $ in Millions, ¥ in Billions	Jun. 30, 2018 USD ($)	Jun. 30, 2018 JPY (¥)	Dec. 31, 2017 JPY (¥)
2.40% senior notes due March 2020
Debt Instrument [Line Items]
Debt instrument, interest rate	2.40%	2.40%	2.40%
Debt instrument, principal amount	$ 550
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%	4.00%	4.00%
Debt instrument, principal amount	$ 350
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%	3.625%	3.625%
Debt instrument, principal amount	$ 700
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%	3.625%	3.625%
Debt instrument, principal amount	$ 750
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Debt instrument, interest rate	3.25%	3.25%	3.25%
Debt instrument, principal amount	$ 450
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Debt instrument, interest rate	2.875%	2.875%	2.875%
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, interest rate	6.90%	6.90%	6.90%
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Debt instrument, interest rate	6.45%	6.45%	6.45%
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%	4.00%	4.00%
.932% senior notes due January 2027
Debt Instrument [Line Items]
Debt instrument, interest rate	0.932%	0.932%	0.932%
Debt instrument, principal amount | ¥		¥ 60.0	¥ 60.0
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Debt instrument, interest rate	2.108%	2.108%	2.108%
Debt instrument, principal amount | ¥		¥ 60.0	¥ 60.0
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Debt instrument, interest rate	0.32%	0.32%	0.32%
Debt instrument, principal amount | ¥		¥ 5.0	¥ 5.0
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	0.47%	0.47%	0.47%
Debt instrument, principal amount | ¥		¥ 25.0	¥ 25.0