Stock-Based Compensation Stock Options (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	11 Months Ended	12 Months Ended		1 Months Ended
	Dec. 31, 2010 Successor [Member]	Dec. 31, 2012 Successor [Member]	Dec. 31, 2011 Successor [Member]	Feb. 12, 2010 Predecessor [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options outstanding, Beginning of period		9,571
Options, Granted in the period		4
Options, Exercised in the period		(2,552)
Options, Cancelled in the period		(92)
Number of options outstanding, End of period		6,931	9,571
Options, Exercisable		6,927
Weighted Average Exercise Price, Beginning of period		$ 56.00
Options, Grants in Period, Weighted Average Exercise Price		$ 85.04
Options, Exercises in Period, Weighted Average Exercise Price		$ 47.00
Options, Cancelled in Period, Weighted Average Exercise Price		$ 81.68
Weighted Average Exercise Price, End of period		$ 59.00	$ 56.00
Options, Exercisable, Weighted Average Exercise Price		$ 58.98
Options, Outstanding, Weighted Average Remaining Contractual Term		4 years 5 months 19 days	4 years 10 months 10 days
Aggregate intrinsic value, Beginning of period		$ 200
Aggregate intrinsic value, End of period		213	200
Options, Exercisable, Aggregate Intrinsic Value		213
Total intrinsic value of options exercised	$ 71	$ 95	$ 55	$ 33