Severance and Leased Real Estate (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended	12 Months Ended		12 Months Ended			3 Months Ended
	Apr. 01, 2011 Severance	Dec. 31, 2011 Severance	Dec. 31, 2012 Severance	Dec. 31, 2011 Acquisition of Qwest Severance	Apr. 02, 2011 Acquisition of Qwest Leased real estate	Dec. 31, 2011 Acquisition of Qwest Leased real estate	Dec. 31, 2012 Acquisition of Qwest Leased real estate	Apr. 01, 2011 Acquisition of Qwest Leased real estate	Dec. 31, 2012 Acquisition of Qwest Ceased-use leased real estate accrual Leased real estate Minimum	Dec. 31, 2012 Acquisition of Qwest Ceased-use leased real estate accrual Leased real estate Maximum	Dec. 31, 2012 Acquisition of Qwest Ceased-use leased real estate accrual Leased real estate Weighted average	Dec. 31, 2010 Predecessor	Mar. 31, 2011 Predecessor Severance	Mar. 31, 2011 Predecessor Leased real estate
Severance and Leased Real Estate
Current portion of leased real estate accrual						$ 27	$ 19
Long-term portion of leased real estate accrual						126	112
Remaining lease terms									2 months 12 days	13 years	9 years
Changes in the entity's accrued liabilities for severance expenses and leased real estate
Balance at the beginning of the period			29				153	168					29	223
Accrued to expense		120	67			15	2						4	4
Payments, net		(99)	(86)			(21)	(24)						(12)	(12)
Reversals and adjustments		(10)	(3)			(9)							(1)
Balance at the end of period	18	29	7			153	131	168					20	215
Additional information
Fair value adjustment	(2)				(47)
Share-based compensation associated with the accelerated vesting of stock awards				$ 12								$ 63