Investments - Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				3 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 FTS International, Inc.	Dec. 31, 2013 FTS International, Inc.	Mar. 31, 2014 Chaparral Energy, Inc.	Dec. 31, 2013 Chaparral Energy, Inc.	Mar. 31, 2014 Sundrop Fuels, Inc.	Sep. 30, 2013 Sundrop Fuels, Inc.	Dec. 31, 2013 Sundrop Fuels, Inc.	Jul. 20, 2011 Sundrop Fuels, Inc.	Mar. 31, 2014 Other Investment Companies [Member]	Jul. 20, 2011 Initial Payment [Member] Sundrop Fuels, Inc.
Schedule of Equity Method Investments [Line Items]
Equity Method Investments			$ 129	$ 138	$ 0	$ 143	$ 134		$ 135	$ 155		$ 35
Marketable Securities, Equity Securities							25
Positive equity method adjustments			15					3
Interest Costs Capitalized							2
Equity method accretion adjustments			6					65
Excess carrying value of investment over underlying equity in net assets			48
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Attributable to Goodwill			14
Proceeds from sales of investments	239	0			209						30
Gain on Sale of Investments					73
Loss on Sale of Investments											$ 6