Intangible Assets (Tables)

3 Months Ended

Jun. 30, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Indefinite-Lived Intangible Assets

	March 31, 2016		Net Additions		June 30, 2016
	(in millions)
FCC licenses (1)	$	36,038	$	102	$	36,140
Trademarks	4,035		—		4,035
Goodwill	6,575		—		6,575
	$	46,648	$	102	$	46,750

Intangible Assets Subject to Amortization

		June 30, 2016							March 31, 2016
	Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
		(in millions)
Customer relationships	4 to 8 years	$	6,923	$	(4,320	)	$	2,603	$	6,923	$	(4,045	)	$	2,878
Other intangible assets:
Favorable spectrum leases	23 years	880		(119		)	761		881		(110		)	771
Favorable tower leases	3 to 7 years	589		(325		)	264		589		(302		)	287
Trademarks	34 years	520		(47		)	473		520		(43		)	477
Other	4 to 10 years	85		(29		)	56		83		(27		)	56
Total other intangible assets		2,074		(520		)	1,554		2,073		(482		)	1,591
Total definite-lived intangible assets		$	8,997	$	(4,840	)	$	4,157	$	8,996	$	(4,527	)	$	4,469