Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Mar. 31, 2011 Predecessor	Dec. 31, 2010 Predecessor
Capital Leases
Assets acquired through capital leases	$ 8	$ 12	$ 28	$ 202
Depreciation expense	73	93	20	51
Cash payments towards capital leases	59	77	18	45
Assets included in property, plant and equipment	401	399
Accumulated depreciation	75	156
Capital lease obligations:
2013		88
2014		73
2015		43
2016		10
2017		6
2018 and thereafter		24
Total minimum payments		244
Less: amount representing interest and executory costs		(39)
Present value of minimum payments		205
Less: current portion		(75)
Long-term portion		$ 130