Commitments, Contingencies and Other Items - Purchase Commitments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Long-term Purchase Commitment
Total	$ 663
Less than 1 Year	336
2 - 3 Years	152
4 - 5 Years	56
After 5 Years	119
Cost of Access Services
Long-term Purchase Commitment
Total	390
Less than 1 Year	276
2 - 3 Years	100
4 - 5 Years	13
After 5 Years	1
Third Party Maintenance Services
Long-term Purchase Commitment
Total	273
Less than 1 Year	60
2 - 3 Years	52
4 - 5 Years	43
After 5 Years	$ 118