Commitments and Contingencies (Details) (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	$ 2		$ 16	$ 116
Depreciation expense	41	50	11	28
Cash payments towards capital leases	35	41	11	25
Assets included in property, plant and equipment	192	188
Accumulated depreciation	41	85
Capital lease obligations:
2013		46
2014		35
2015		21
2016		2
2017		1
2018 and thereafter		6
Total minimum payments		111
Less: amount representing interest and executory costs		(14)
Present value of minimum payments		97
Less: current portion		(40)
Long-term portion		$ 57