Acquisitions, Dispositions And Other Adjustments (Held-For-Sale) (Narrative) (Details) - Puerto Rico and U.S. Virgin Islands Wireline and Wireless Operations [Member] - Disposal Group, Held-for-sale, Not Discontinued Operations [Member] - USD ($) $ in Millions	1 Months Ended
	Oct. 31, 2019	Sep. 30, 2019
Assets Held-For-Sale [Line Items]
Assets held-for-sale transaction price		$ 1,950
Other Current Assets [Member]
Assets Held-For-Sale [Line Items]
Property, plant and equipment - net		700
Goodwill		300
Accounts Payable and Accrued Liabilities [Member]
Assets Held-For-Sale [Line Items]
Net tax liabilities		400
FCC Licenses [Member] | Other Current Assets [Member]
Assets Held-For-Sale [Line Items]
Indefinite-lived Intangible Assets		$ 1,100
Subsequent Event [Member]
Assets Held-For-Sale [Line Items]
Date of agreement	Oct. 01, 2019
Timing of Disposal	We expect the transaction to close in the first half of 2020, subject to customary closing conditions.