Acquisitions (Narrative) (Details) item in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) item	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) item	Sep. 30, 2014 USD ($)
Business Acquisition [Line Items]
Acquisition and integration costs	$ 58,000,000	$ 42,000,000	$ 150,000,000	$ 72,000,000
Capital Expenditures Integration Activities			101,000,000	82,000,000
Revenue	1,424,000,000	1,141,000,000	4,163,000,000	3,442,000,000
Operating income	207,000,000	$ 197,000,000	563,000,000	647,000,000
Debt Instrument, Face Amount	6,600,000,000		6,600,000,000
Connecticut Operations [Member]
Business Acquisition [Line Items]
Acquisition purchase price	2,018,000,000		2,018,000,000
Acquisition and integration costs			38,000,000	72,000,000
Acquisition costs			1,000,000	3,000,000
Integration costs			37,000,000	69,000,000
Capital Expenditures Integration Activities			23,000,000	$ 82,000,000
Revenue			792,000,000
Operating income			74,000,000
Purchase Price Allocation Adjustment for Deferred Taxes	71,000,000		71,000,000
Verizon Transaction [Member]
Business Acquisition [Line Items]
Acquisition purchase price	$ 10,540,000,000		10,540,000,000
Acquisition and integration costs			112,000,000
Acquisition costs			37,000,000
Integration costs			75,000,000
Capital Expenditures Integration Activities			$ 78,000,000
Number of voice connections acquired | item	3.5		3.5
Number of broadband connections acquired | item	2.2		2.2
Number of video connections acquired | item	1.2		1.2
Extension term of collective bargaining agreements			2 years
Connect America Funding Conditionally Accepted			$ 49,000,000
Proceeds from Issuance or Sale of Equity			2,750,000,000
2015 JP Morgan Credit Agreement [Member]
Business Acquisition [Line Items]
Debt Instrument, Face Amount	$ 1,500,000,000		$ 1,500,000,000