Segment Reporting Total Assets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total assets	$ 12,436.2	$ 12,423.8
Canada
Segment Reporting Information [Line Items]
Total assets	6,394.2	6,541.6
U.S.
Segment Reporting Information [Line Items]
Total assets	2,613.1	2,487.9
U.K.
Segment Reporting Information [Line Items]
Total assets	2,251.6	2,293.4
MCI
Segment Reporting Information [Line Items]
Total assets	152.3	151.7
Corporate [Member]
Segment Reporting Information [Line Items]
Total assets	1,024.7	948.9
Discontinued operations
Segment Reporting Information [Line Items]
Total assets	$ 0.3	$ 0.3