NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Notes Payable (Details) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Notes payable and lease obligations	[1]	$ 6,233	$ 5,778
Finance lease obligations		13	13
Operating lease obligations	[1]	125	0
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Notes payable and lease obligations		348	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		746	746
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Notes payable and lease obligations		448	447
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Notes payable and lease obligations		298	297
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		394	394
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Notes payable and lease obligations		540	540
.932% senior notes due January 2027
Debt Instrument [Line Items]
Notes payable and lease obligations		553	538
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Notes payable and lease obligations		270	262
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Notes payable and lease obligations		140	136
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Notes payable and lease obligations		82	79
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Notes payable and lease obligations		551	536
.963% perpetual subordinated bonds callable April 2024
Debt Instrument [Line Items]
Notes payable and lease obligations		276	0
Yen-denominated loan variable interest rate due September 2026
Debt Instrument [Line Items]
Notes payable and lease obligations		46	45
Yen-denominated loan variable rate due September 2029
Debt Instrument [Line Items]
Notes payable and lease obligations		$ 231	$ 225

[1] See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases.