Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies Disclosure [Line Items]
Rent expense under operating leases, including co-location arrangements	$ 448,000,000	$ 380,000,000	$ 293,000,000
Other non-cancelable contractual obligations	2,100,000,000
Unused letters of credit	89,000,000
Divestitures, total consideration	2,350,000,000
Minimum
Commitments and Contingencies Disclosure [Line Items]
Operating lease, expiration date	2013
Maximum
Commitments and Contingencies Disclosure [Line Items]
Operating lease, expiration date	2063
Mobile
Commitments and Contingencies Disclosure [Line Items]
Unused letters of credit	45,000,000
Building | Building Purchases
Commitments and Contingencies Disclosure [Line Items]
Future rental income related to leases assumed in connection with building purchases	$ 649,000,000