Commitments and Contingencies (Future Minimum Lease Commitments) (Details) $ in Millions	Mar. 31, 2016 USD ($)
Operating leases
Total	$ 14,078
2015	2,195
2016	2,148
2017	2,072
2018	1,958
2019	1,820
2020 and thereafter	3,885
Spectrum leases and service credits
Total	6,707
2015	212
2016	219
2017	221
2018	224
2019	226
2020 and thereafter	5,605
Minimum Lease Payments, Sale Leaseback Transactions	651
Minimum Lease Payments, Sale Leaseback Transactions, Next Twelve Months	580
Minimum Lease Payments, Sale Leaseback Transactions, within Two Years	71
Minimum Lease Payments, Sale Leaseback Transactions, within Three Years	0
Minimum Lease Payments, Sale Leaseback Transactions, within Four Years	0
Minimum Lease Payments, Sale Leaseback Transactions, within Five Years	0
Minimum Lease Payments, Sale Leaseback Transactions, Thereafter	0
Purchase orders and other commitments
Total	11,224
2015	7,192
2016	1,428
2017	951
2018	499
2019	354
2020 and thereafter	800
Total future minimum commitments
Total	32,660
2015	10,179
2016	3,866
2017	3,244
2018	2,681
2019	2,400
2020 and thereafter	$ 10,290