DEBT AND FINANCING ARRANGEMENTS - Carrying Value of Outstanding Debt (Detail) - USD ($) | Apr. 01, 2020 | Sep. 30, 2021 | Apr. 01, 2021 | Jan. 15, 2021 | Dec. 31, 2020 | Dec. 31, 2019 |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 22,274,000,000 | | | | |
Total debt | | 22,106,000,000 | | | $ 24,654,000,000 | |
Less current maturities | | (1,268,000,000) | | | (2,623,000,000) | |
Long-Term Debt and Finance Leases | | 20,838,000,000 | | | 22,031,000,000 | |
Senior notes | 3.125% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 0 | | | | |
Debt instrument, stated interest rate | | 3.125% | | 3.125% | | |
Total debt | | $ 0 | | | 1,507,000,000 | |
Senior notes | 2.050% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 0 | | | | |
Debt instrument, stated interest rate | | 2.05% | 2.05% | | | |
Total debt | | $ 0 | | | 700,000,000 | |
Senior notes | 2.450% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,000,000,000 | | | | |
Debt instrument, stated interest rate | | 2.45% | | | | |
Total debt | | $ 1,016,000,000 | | | 1,028,000,000 | |
Senior notes | 2.350% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 600,000,000 | | | | |
Debt instrument, stated interest rate | | 2.35% | | | | |
Total debt | | $ 600,000,000 | | | 599,000,000 | |
Senior notes | 2.500% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,000,000,000 | | | | |
Debt instrument, stated interest rate | | 2.50% | | | | |
Total debt | | $ 998,000,000 | | | 997,000,000 | |
Senior notes | 2.800% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 500,000,000 | | | | |
Debt instrument, stated interest rate | | 2.80% | | | | |
Total debt | | $ 498,000,000 | | | 498,000,000 | |
Senior notes | 2.200% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 400,000,000 | | | | |
Debt instrument, stated interest rate | | 2.20% | | | | |
Total debt | | $ 399,000,000 | | | 398,000,000 | |
Senior notes | 3.900% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,000,000,000 | | | | |
Debt instrument, stated interest rate | | 3.90% | | | | |
Total debt | | $ 996,000,000 | | | 995,000,000 | |
Senior notes | 2.400% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 500,000,000 | | | | |
Debt instrument, stated interest rate | | 2.40% | | | | |
Total debt | | $ 498,000,000 | | | 498,000,000 | |
Senior notes | 3.050% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,000,000,000 | | | | |
Debt instrument, stated interest rate | | 3.05% | | | | |
Total debt | | $ 994,000,000 | | | 993,000,000 | |
Senior notes | 3.400% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 750,000,000 | | | | |
Debt instrument, stated interest rate | | 3.40% | | | | |
Total debt | | $ 746,000,000 | | | 746,000,000 | |
Senior notes | 2.500% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 400,000,000 | | | | |
Debt instrument, stated interest rate | | 2.50% | | | | |
Total debt | | $ 397,000,000 | | | 397,000,000 | |
Senior notes | 4.450% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 750,000,000 | | | | |
Debt instrument, stated interest rate | | 4.45% | | | | |
Total debt | | $ 743,000,000 | | | 743,000,000 | |
Senior notes | 6.200% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,500,000,000 | | | | |
Debt instrument, stated interest rate | | 6.20% | | | | |
Total debt | | $ 1,484,000,000 | | | 1,483,000,000 | |
Senior notes | 5.200% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 500,000,000 | | | | |
Debt instrument, stated interest rate | | 5.20% | | | | |
Total debt | | $ 494,000,000 | | | 493,000,000 | |
Senior notes | 4.875% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 500,000,000 | | | | |
Debt instrument, stated interest rate | | 4.875% | | | | |
Total debt | | $ 491,000,000 | | | 490,000,000 | |
Senior notes | 3.625% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 375,000,000 | | | | |
Debt instrument, stated interest rate | | 3.625% | | | | |
Total debt | | $ 368,000,000 | | | 368,000,000 | |
Senior notes | 3.400% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 500,000,000 | | | | |
Debt instrument, stated interest rate | | 3.40% | | | | |
Total debt | | $ 492,000,000 | | | 491,000,000 | |
Senior notes | 3.750% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,150,000,000 | | | | |
Debt instrument, stated interest rate | | 3.75% | | | | |
Total debt | | $ 1,137,000,000 | | | 1,137,000,000 | |
Senior notes | 4.250% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 750,000,000 | | | | |
Debt instrument, stated interest rate | | 4.25% | | | | |
Total debt | | $ 743,000,000 | | | 742,000,000 | |
Senior notes | 3.400% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 700,000,000 | | | | |
Debt instrument, stated interest rate | | 3.40% | | | | |
Total debt | | $ 688,000,000 | | | 688,000,000 | |
Senior notes | 5.300% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 1,250,000,000 | | | | |
Debt instrument, stated interest rate | | 5.30% | | | | |
Total debt | | $ 1,231,000,000 | | | 1,231,000,000 | |
Senior notes | Floating-rate senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 0 | | | | |
Total debt | | 0 | | | 350,000,000 | |
Senior notes | Floating-rate senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 400,000,000 | | | | |
Total debt | | 400,000,000 | | | 399,000,000 | |
Senior notes | Floating-rate senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 500,000,000 | | | | |
Total debt | | 500,000,000 | | | 499,000,000 | |
Senior notes | Floating-rate senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 1,039,000,000 | | | | |
Total debt | | 1,027,000,000 | | | 1,027,000,000 | |
Senior notes | 7.620% debentures(1) | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 276,000,000 | | | | |
Debt instrument, stated interest rate | 7.62% | 7.62% | | | | 8.375% |
Total debt | | $ 280,000,000 | | | 281,000,000 | |
Debt instrument, term | 10 years | | | | | |
Senior notes | Canadian senior note 2.125% | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 588,000,000 | | | | |
Debt instrument, stated interest rate | | 2.125% | | | | |
Total debt | | $ 586,000,000 | | | 583,000,000 | |
Pound Sterling notes | 5.500% notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 89,000,000 | | | | |
Debt instrument, stated interest rate | | 5.50% | | | | |
Total debt | | $ 88,000,000 | | | 90,000,000 | |
Pound Sterling notes | 5.125% notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 612,000,000 | | | | |
Debt instrument, stated interest rate | | 5.125% | | | | |
Total debt | | $ 581,000,000 | | | 586,000,000 | |
Euro Senior Notes | 0.375% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 811,000,000 | | | | |
Debt instrument, stated interest rate | | 0.375% | | | | |
Total debt | | $ 808,000,000 | | | 857,000,000 | |
Euro Senior Notes | 1.625% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 811,000,000 | | | | |
Debt instrument, stated interest rate | | 1.625% | | | | |
Total debt | | $ 807,000,000 | | | 856,000,000 | |
Euro Senior Notes | 1.000% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 579,000,000 | | | | |
Debt instrument, stated interest rate | | 1.00% | | | | |
Total debt | | $ 576,000,000 | | | 611,000,000 | |
Euro Senior Notes | 1.500% senior notes | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | $ 579,000,000 | | | | |
Debt instrument, stated interest rate | | 1.50% | | | | |
Total debt | | $ 575,000,000 | | | 611,000,000 | |
Facility notes and bonds | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 320,000,000 | | | | |
Total debt | | 320,000,000 | | | 320,000,000 | |
Other debt | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Debt Instrument, Face Amount | | 3,000,000 | | | | |
Total debt | | $ 3,000,000 | | | $ 5,000,000 | |