Financial Instruments (Schedule of Short-term and Long-term Classification) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	$ 0.0	$ (1,494.2)
Long-term debt, including current portion	(16,348.7)	(13,638.5)
Carrying Amount
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, including current portion	(16,595.3)	(13,823.0)
Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, including current portion	(19,038.9)	(15,150.0)
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, including current portion	0.0	0.0
Significant Other Observable Inputs (Level 2) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, including current portion	(19,038.9)	(15,150.0)
Significant Unobservable Inputs (Level 3) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, including current portion	0.0	0.0
Commercial Paper | Carrying Amount
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	0.0	(1,494.2)
Commercial Paper | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	0.0	(1,491.6)
Commercial Paper | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	0.0	0.0
Commercial Paper | Significant Other Observable Inputs (Level 2) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	0.0	(1,491.6)
Commercial Paper | Significant Unobservable Inputs (Level 3) | Fair Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term commercial paper borrowings	$ 0.0	$ 0.0