Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Fair Value and Carrying Value of Long-term Debt

The carrying values of financial instruments equal or approximate their fair values with the exception of long-term debt:

(in millions of Canadian dollars)	March 31, 2018		December 31, 2017
Long-term debt (including current maturities):
Fair value	$	9,598	$	9,680
Carrying value	8,357		8,159