Acquisitions (Narrative) (Details) item in Millions, customer in Millions, $ in Millions		3 Months Ended	6 Months Ended
	Apr. 01, 2016 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($) customer item	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Cash paid for acquisition	$ 9,871			$ 9,886
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities			$ 61
Goodwill, Purchase Accounting Adjustments			98
Capital Expenditures Integration Activities			5	88
CTF Transaction [Member]
Business Acquisition [Line Items]
Acquisition purchase price			10,540
Working Capital and Net Debt Settlement Payments Received			$ 15
Number of voice connections acquired | customer			2.5
Number of broadband connections acquired | item			2.1
Number of video connections acquired | item			1.2
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles			$ 100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles			2,262		$ 2,162
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Related to Previous Period		$ 20
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment			(140)
Capital Expenditures Integration Activities			$ 5	$ 88