v3.8.0.1
Borrowings - Additional Information (Detail)
3 Months Ended
Mar. 31, 2018
USD ($)
Commercial Paper [Member]  
Debt Instrument [Line Items]  
Maximum amount available under facility $ 4,000,000,000
Amount outstanding under credit facility 0
2018 Revolving Credit Facility [Member]  
Debt Instrument [Line Items]  
Unsecured revolving credit facility 4,000,000,000
Additional amount available, subject to lender credit approval 1,000,000,000
Maximum amount available under facility 5,000,000,000
Amount outstanding under credit facility $ 0
Extended debt instrument maturity date 2023-03
Line of credit facility, covenant terms The 2018 credit facility requires the Company not to exceed a maximum leverage ratio (ratio of net debt to earnings before interest, taxes, depreciation and amortization, where net debt equals total debt less unrestricted cash) of 3 to 1
Line of credit facility, covenant compliance satisfied with a ratio of less than 1 to 1