Carrying Value of Outstanding Debt (Detail) - USD ($) | 3 Months Ended | |
Mar. 31, 2019 | Dec. 31, 2018 |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 23,312,000,000 | |
Debt instrument, stated interest rate | 8.375% | |
Total debt | $ 23,166,000,000 | $ 22,736,000,000 |
Less current maturities | (2,789,000,000) | (2,805,000,000) |
Long-Term Debt and Finance Leases | 20,377,000,000 | 19,931,000,000 |
Commercial Paper | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,644,000,000 | |
Maturity - Minimum Date | Mar. 31, 2019 | |
Maturity - Maximum Date | Dec. 31, 2020 | |
Total debt | $ 1,644,000,000 | 2,662,000,000 |
Senior notes | 5.50% stated rate | | |
Debt Instrument [Line Items] | | |
Maturity - Maximum Date | Dec. 31, 2018 | |
Debt instrument, stated interest rate | 5.50% | |
Senior notes | 5.125% stated rate | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,000,000,000 | |
Maturity - Maximum Date | Dec. 31, 2019 | |
Debt instrument, stated interest rate | 5.125% | |
Total debt | $ 1,000,000,000 | 998,000,000 |
Senior notes | 3.125% stated rate | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2021 | |
Debt instrument, stated interest rate | 3.125% | |
Total debt | $ 1,522,000,000 | 1,492,000,000 |
Senior notes | 2.050% senior notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 700,000,000 | |
Maturity - Maximum Date | Dec. 31, 2021 | |
Debt instrument, stated interest rate | 2.05% | |
Total debt | $ 698,000,000 | 698,000,000 |
Senior notes | 2.400% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2026 | |
Debt instrument, stated interest rate | 2.40% | |
Total debt | $ 498,000,000 | 498,000,000 |
Senior notes | 3.050% senior notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,000,000,000 | |
Maturity - Maximum Date | Dec. 31, 2027 | |
Debt instrument, stated interest rate | 3.05% | |
Total debt | $ 991,000,000 | 991,000,000 |
Senior notes | 3.400% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 750,000,000 | |
Maturity - Maximum Date | Dec. 31, 2029 | |
Debt instrument, stated interest rate | 3.40% | |
Total debt | $ 745,000,000 | 0 |
Senior notes | 2.45% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,000,000,000 | |
Maturity - Maximum Date | Dec. 31, 2022 | |
Debt instrument, stated interest rate | 2.45% | |
Total debt | $ 983,000,000 | 1,023,000,000 |
Senior notes | 2.350% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 600,000,000 | |
Maturity - Maximum Date | Dec. 31, 2022 | |
Debt instrument, stated interest rate | 2.35% | |
Total debt | $ 598,000,000 | 597,000,000 |
Senior notes | 2.500% senior notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,000,000,000 | |
Maturity - Maximum Date | Dec. 31, 2023 | |
Debt instrument, stated interest rate | 2.50% | |
Total debt | $ 994,000,000 | 994,000,000 |
Senior notes | 2.800% senior notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2024 | |
Debt instrument, stated interest rate | 2.80% | |
Total debt | $ 496,000,000 | 496,000,000 |
Senior notes | 6.20% stated rate | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2038 | |
Debt instrument, stated interest rate | 6.20% | |
Total debt | $ 1,482,000,000 | 1,482,000,000 |
Senior notes | 4.875% stated rate | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2040 | |
Debt instrument, stated interest rate | 4.875% | |
Total debt | $ 490,000,000 | 490,000,000 |
Senior notes | 3.625% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 375,000,000 | |
Maturity - Maximum Date | Dec. 31, 2042 | |
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 | |
Maturity - Maximum Date | Dec. 31, 2046 | |
Debt instrument, stated interest rate | 3.40% | |
Total debt | $ 491,000,000 | 491,000,000 |
Senior notes | 3.750% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,150,000,000 | |
Maturity - Maximum Date | Dec. 31, 2047 | |
Debt instrument, stated interest rate | 3.75% | |
Total debt | $ 1,136,000,000 | 1,136,000,000 |
Senior notes | 4.250% senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 750,000,000 | |
Maturity - Maximum Date | Dec. 31, 2049 | |
Debt instrument, stated interest rate | 4.25% | |
Total debt | $ 742,000,000 | 0 |
Senior notes | Floating Rate Senior Notes 2 [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 350,000,000 | |
Maturity - Maximum Date | Dec. 31, 2021 | |
Total debt | $ 349,000,000 | 349,000,000 |
Senior notes | 8.375% debentures | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 424,000,000 | |
Maturity - Maximum Date | Dec. 31, 2020 | |
Debt instrument, stated interest rate | 8.375% | |
Total debt | $ 432,000,000 | 419,000,000 |
Senior notes | 8.375% debentures | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 276,000,000 | |
Maturity - Maximum Date | Dec. 31, 2030 | |
Total debt | $ 281,000,000 | 274,000,000 |
Senior notes | Canadian senior note 2.125% | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 558,000,000 | |
Maturity - Maximum Date | Dec. 31, 2024 | |
Debt instrument, stated interest rate | 2.125% | |
Total debt | $ 555,000,000 | 548,000,000 |
Senior notes | Floating rate senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 400,000,000 | |
Maturity - Maximum Date | Dec. 31, 2022 | |
Total debt | $ 399,000,000 | 399,000,000 |
Senior notes | Floating Rate Senior Notes 3 [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 500,000,000 | |
Maturity - Maximum Date | Dec. 31, 2023 | |
Total debt | $ 499,000,000 | 499,000,000 |
Senior notes | Floating Rate Senior Notes 4 [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 1,041,000,000 | |
Maturity - Minimum Date | Dec. 31, 2049 | |
Maturity - Maximum Date | Dec. 31, 2067 | |
Total debt | $ 1,028,000,000 | 1,029,000,000 |
Capital Lease Obligations | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 525,000,000 | |
Maturity - Minimum Date | Dec. 31, 2019 | |
Maturity - Maximum Date | Dec. 31, 3005 | |
Total debt | $ 525,000,000 | 534,000,000 |
Pound Sterling notes | 5.500% notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 87,000,000 | |
Maturity - Maximum Date | Dec. 31, 2031 | |
Debt instrument, stated interest rate | 5.50% | |
Total debt | $ 86,000,000 | 84,000,000 |
Pound Sterling notes | 5.125% notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 595,000,000 | |
Maturity - Maximum Date | Jan. 1, 2050 | |
Debt instrument, stated interest rate | 5.125% | |
Total debt | $ 564,000,000 | 546,000,000 |
Euro Senior Notes | 0.375% Euro Senior Notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 786,000,000 | |
Maturity - Maximum Date | Dec. 31, 2023 | |
Debt instrument, stated interest rate | 0.375% | |
Total debt | $ 782,000,000 | 797,000,000 |
Euro Senior Notes | 1.625% Euro Senior Notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 786,000,000 | |
Maturity - Maximum Date | Dec. 31, 2025 | |
Debt instrument, stated interest rate | 1.625% | |
Total debt | $ 782,000,000 | 798,000,000 |
Euro Senior Notes | 1.000% notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 562,000,000 | |
Maturity - Maximum Date | Dec. 31, 2028 | |
Debt instrument, stated interest rate | 1.00% | |
Total debt | $ 558,000,000 | 570,000,000 |
Euro Senior Notes | 1.500% Euro Senior Notes [Member] | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 562,000,000 | |
Maturity - Maximum Date | Dec. 31, 2032 | |
Debt instrument, stated interest rate | 1.50% | |
Total debt | $ 558,000,000 | 569,000,000 |
Euro Senior Notes | Floating-rate senior notes | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 562,000,000 | |
Maturity - Maximum Date | Dec. 31, 2020 | |
Total debt | $ 561,000,000 | 572,000,000 |
Facility notes and bonds | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 320,000,000 | |
Maturity - Minimum Date | Dec. 31, 2029 | |
Maturity - Maximum Date | Dec. 31, 2045 | |
Total debt | $ 320,000,000 | 320,000,000 |
Other debt | | |
Debt Instrument [Line Items] | | |
Debt Instrument, Face Amount | $ 9,000,000 | |
Maturity - Minimum Date | Dec. 31, 2019 | |
Maturity - Maximum Date | Dec. 31, 2022 | |
Total debt | $ 9,000,000 | $ 13,000,000 |