Fair Value Measurements Level Three Assets (Details)	9 Months Ended
	Mar. 31, 2017 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at July 1, 2016	$ 71,000,000
Net realized gain (loss)	1,000,000
Redemptions	(72,000,000)
Net unrealized gain	1,000,000
Fair value at March 31, 2017	1,000,000
2017 Call Options [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at July 1, 2016	70,000,000
Net realized gain (loss)	2,000,000
Redemptions	(72,000,000)
Net unrealized gain	0
Fair value at March 31, 2017	0
2020 Call Options [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at July 1, 2016	1,000,000
Net realized gain (loss)	(1,000,000)
Redemptions	0
Net unrealized gain	1,000,000
Fair value at March 31, 2017	$ 1,000,000