Acquisitions (Details) - Lightower Acquisition [Member] $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	$ 7,100
Fiber Miles Acquired	32,000
Business Acquisition, Date of Acquisition Agreement	Nov. 01, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	$ 99
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	2,194
Business Acquisition, Goodwill	3,168	[1]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets	2,177	[2]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	30
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(174)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities	(342)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 7,152	[3]

[1] The preliminary purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on:•the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions,•the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce.

[2] Predominately comprised of site rental contracts and customer relationships.

[3] The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition.