Segment Reporting (Revenue by Major Category) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 4,584.6	$ 5,074.1	$ 9,014.5	$ 9,662.1
Cable [Member]
Segment Reporting Information [Line Items]
Revenues	3,165.9	3,816.2	6,260.2	7,475.8
Cable Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	3,022.2	3,662.2	5,959.0	7,176.2
Cable Video Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	1,267.4	1,584.3	2,491.7	3,123.3
Cable Broadband Internet Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	1,149.4	1,315.2	2,265.7	2,554.2
Cable Fixed-line Telephony Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	605.4	762.7	1,201.6	1,498.7
Cable Non-Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	143.7	154.0	301.2	299.6
Residential [Member]
Segment Reporting Information [Line Items]
Revenues	3,767.3	4,398.5	7,444.5	8,472.2
Mobile Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	432.5	401.0	856.8	678.4
Mobile Non-Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	168.9	181.3	327.5	318.0
Mobile Residential [Member]
Segment Reporting Information [Line Items]
Revenues	601.4	582.3	1,184.3	996.4
Business to Business [Member]
Segment Reporting Information [Line Items]
Revenues	763.0	649.6	1,463.4	1,146.1
Business to Business Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	133.8	124.2	249.5	231.1
Business to Business Non-Subscription [Member]
Segment Reporting Information [Line Items]
Revenues	629.2	525.4	1,213.9	915.0
Other Category [Member]
Segment Reporting Information [Line Items]
Revenues	$ 54.3	$ 26.0	$ 106.6	$ 43.8