Condensed Consolidating Financial Information - Interim Condensed Consolidating Statements of Income (Details) - CAD CAD in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Freight	CAD 1,548	CAD 1,630
Non-freight	43	35
Total revenues	1,591	1,665
Operating expenses
Compensation and benefits	329	378
Fuel	125	195
Materials	56	52
Equipment rents	45	42
Depreciation and amortization	162	146
Purchased services and other	221	240
Total operating expenses	938	1,053
Operating income	653	612
Less:
Other income and charges	(181)	73
Net interest (income) expense	124	85
Income before income tax expense	710	454
Less: Income tax (recovery) expense	170	134
Add: Equity in net earnings of subsidiaries	0	0
Net income	540	320
Consolidating Adjustments and Eliminations [Member]
Revenues
Freight	0	0
Non-freight	(86)	(83)
Total revenues	(86)	(83)
Operating expenses
Compensation and benefits	2	0
Fuel	0	0
Materials	8	0
Equipment rents	0	0
Depreciation and amortization	0	0
Purchased services and other	(96)	(83)
Total operating expenses	(86)	(83)
Operating income	0	0
Less:
Other income and charges	0	0
Net interest (income) expense	0	0
Income before income tax expense	0	0
Less: Income tax (recovery) expense	0	0
Add: Equity in net earnings of subsidiaries	(571)	(515)
Net income	(571)	(515)
CPRL (Parent Guarantor) [Member]
Revenues
Freight	0	0
Non-freight	0	0
Total revenues	0	0
Operating expenses
Compensation and benefits	0	0
Fuel	0	0
Materials	0	0
Equipment rents	0	0
Depreciation and amortization	0	0
Purchased services and other	0	0
Total operating expenses	0	0
Operating income	0	0
Less:
Other income and charges	(69)	18
Net interest (income) expense	(1)	0
Income before income tax expense	70	(18)
Less: Income tax (recovery) expense	9	(4)
Add: Equity in net earnings of subsidiaries	479	334
Net income	540	320
CPRC (Subsidiary Issuer) [Member]
Revenues
Freight	1,097	1,119
Non-freight	33	29
Total revenues	1,130	1,148
Operating expenses
Compensation and benefits	201	262
Fuel	103	161
Materials	38	43
Equipment rents	54	36
Depreciation and amortization	107	102
Purchased services and other	136	142
Total operating expenses	639	746
Operating income	491	402
Less:
Other income and charges	(138)	86
Net interest (income) expense	131	96
Income before income tax expense	498	220
Less: Income tax (recovery) expense	111	67
Add: Equity in net earnings of subsidiaries	92	181
Net income	479	334
Non-Guarantor Subsidiaries [Member]
Revenues
Freight	451	511
Non-freight	96	89
Total revenues	547	600
Operating expenses
Compensation and benefits	126	116
Fuel	22	34
Materials	10	9
Equipment rents	(9)	6
Depreciation and amortization	55	44
Purchased services and other	181	181
Total operating expenses	385	390
Operating income	162	210
Less:
Other income and charges	26	(31)
Net interest (income) expense	(6)	(11)
Income before income tax expense	142	252
Less: Income tax (recovery) expense	50	71
Add: Equity in net earnings of subsidiaries	0	0
Net income	CAD 92	CAD 181