NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Notes Payable (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Notes payable and lease obligations	$ 6,758	$ 6,569
Finance lease obligations	12	12
Operating lease obligations	149	149
4.00% senior notes paid January 2020
Debt Instrument [Line Items]
Notes payable and lease obligations	0	348
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Notes payable and lease obligations	698	698
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Notes payable and lease obligations	747	747
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Notes payable and lease obligations	448	448
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Notes payable and lease obligations	298	298
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Notes payable and lease obligations	220	220
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Notes payable and lease obligations	254	254
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Notes payable and lease obligations	393	394
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Notes payable and lease obligations	541	541
.300% senior notes due September 2025
Debt Instrument [Line Items]
Notes payable and lease obligations	113	0
.932% senior notes due January 2027
Debt Instrument [Line Items]
Notes payable and lease obligations	549	545
.500% senior noted due December 2029
Debt Instrument [Line Items]
Notes payable and lease obligations	115	114
.550% senior notes due March 2030
Debt Instrument [Line Items]
Notes payable and lease obligations	121	0
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Notes payable and lease obligations	268	266
.843% senior notes due December 2031
Debt Instrument [Line Items]
Notes payable and lease obligations	85	84
.750% senior notes due March 2032
Debt Instrument [Line Items]
Notes payable and lease obligations	189	0
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Notes payable and lease obligations	139	138
.934% senior notes due December 2034
Debt Instrument [Line Items]
Notes payable and lease obligations	89	88
.830% senior notes due March 2035
Debt Instrument [Line Items]
Notes payable and lease obligations	97	0
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Notes payable and lease obligations	81	81
1.122% senior notes due December 2039
Debt Instrument [Line Items]
Notes payable and lease obligations	57	57
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Notes payable and lease obligations	547	543
.936% subordinate bond due April 2049
Debt Instrument [Line Items]
Notes payable and lease obligations	274	272
Yen-denominated loan variable interest rate due September 2026
Debt Instrument [Line Items]
Notes payable and lease obligations	46	45
Yen-denominated loan variable interest rate due September 2029
Debt Instrument [Line Items]
Notes payable and lease obligations	$ 228	$ 227