Commitments, Contingencies and Other Items - Other Commitments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 year	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies Disclosure [Abstract]
Amount outstanding under letters of credit	$ 31	$ 33
Collateralized Financings	29	29
Payments under these right-of-way agreements	172	135	127
Rent expense, including common area maintenance, under non-cancelable lease agreements	308	232	203
Right-of-Way Agreements
Right-of-Way Agreements, 2013	115
Right-of-Way Agreements, 2014	60
Right-of-Way Agreements, 2015	52
Right-of-Way Agreements, 2016	48
Right-of-Way Agreements, 2017	44
Right-of-Way Agreements, Thereafter	386
Right-of-Way Agreements, Total	705
Facilities
Facilities, 2013	255
Facilities, 2014	214
Facilities, 2015	187
Facilities, 2016	145
Facilities, 2017	128
Facilities, Thereafter	498
Facilities, Total	1,427
Total
Right-of-Way Agreements and Facilities, 2013	370
Right-of-Way Agreements and Facilities, 2014	274
Right-of-Way Agreements and Facilities, 2015	239
Right-of-Way Agreements and Facilities, 2016	193
Right-of-Way Agreements and Facilities, 2017	172
Right-of-Way Agreements and Facilities, Thereafter	884
Right-of-Way Agreements and Facilities, Total	2,132
Future Minimum Sublease Receipts
2013	16
2014	13
2015	9
2016	8
2017	6
Thereafter	11
Total	$ 63
Period of Right-of-Way Agreements with cancelable agreements (in years)	1