Debt Obligations - Instruments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument
Total debt outstanding	$ 1,760	$ 1,970
6.05% Senior Notes due 2013
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	6.05%
6.20% Senior Notes due 2017
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	6.20%
8.125% Senior Notes due 2019
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	8.125%
7.00% Senior Notes due 2029
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	7.00%
7.00% Senior Notes due 2018
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	7.00%
Successor
Debt Instrument
Net premiums on long-term debt	0
Unamortized fair value adjustments	136
Total debt outstanding	1,757
Current portion of long-term debt	(258)
Total long-term debt	1,499
Successor | 6.05% Senior Notes due 2013
Debt Instrument
Senior Notes	250
Successor | 6.20% Senior Notes due 2017
Debt Instrument
Senior Notes	300
Successor | 8.125% Senior Notes due 2019
Debt Instrument
Senior Notes	150
Successor | 7.00% Senior Notes due 2029
Debt Instrument
Senior Notes	66
Successor | 7.00% Senior Notes due 2018
Debt Instrument
Senior Notes	400
Successor | Term Loans due 2012
Debt Instrument
Term Loans	0
Successor | Term Loan due 2015
Debt Instrument
Term Loans	455
Predecessor
Debt Instrument
Net premiums on long-term debt		3
Unamortized fair value adjustments		0
Total debt outstanding		1,966
Current portion of long-term debt		(342)
Total long-term debt		1,624
Predecessor | 6.05% Senior Notes due 2013
Debt Instrument
Senior Notes		250
Predecessor | 6.20% Senior Notes due 2017
Debt Instrument
Senior Notes		300
Predecessor | 8.125% Senior Notes due 2019
Debt Instrument
Senior Notes		150
Predecessor | 7.00% Senior Notes due 2029
Debt Instrument
Senior Notes		66
Predecessor | 7.00% Senior Notes due 2018
Debt Instrument
Senior Notes		400
Predecessor | Term Loans due 2012
Debt Instrument
Term Loans		797
Predecessor | Term Loan due 2015
Debt Instrument
Term Loans		$ 0