Debt - Recourse Debt (Details) (USD $)	3 Months Ended			1 Months Ended		0 Months Ended	1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jun. 30, 2015	Mar. 31, 2015	Feb. 28, 2014	Mar. 07, 2014	Apr. 30, 2015	Apr. 06, 2015
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ 23,000,000	$ 134,000,000
Recourse Debt [Member] | 5.50% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Interest rate on senior notes						5.50%
Issued senior notes						750,000,000
Recourse Debt [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt			(82,000,000)
Recourse Debt [Member] | 7.75% Senior Notes Due 2015 [Member]
Debt Instrument [Line Items]
Redeemed notes				151,000,000
Interest rate on senior notes	7.75%			7.75%
Recourse Debt [Member] | 9.75% Senior Notes Due 2016 [Member] [Domain]
Debt Instrument [Line Items]
Redeemed notes				164,000,000
Interest rate on senior notes	9.75%			9.75%
Recourse Debt [Member] | 7.75% Senior Notes Due 2014 [Member]
Debt Instrument [Line Items]
Redeemed notes					110,000,000
Interest rate on senior notes					7.75%
Recourse Debt [Member] | 8.0% Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Redeemed notes						625,000,000
Interest rate on senior notes						8.00%
Loss on extinguishment of debt						132,000,000
Recourse Debt [Member] | 8.0% Senior Notes Due 2017 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Redeemed notes							$ 344,000,000
Interest rate on senior notes								8.00%