Schedule II - Condensed Financial Information of Registrant - Condensed Balance Sheet of Registrant (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
ASSETS
Cash and cash equivalents	$ 1,319.2	$ 1,899.7	$ 1,470.7	$ 1,137.4
Receivables, net	585.1	611.3
Properties, net	462.9	441.0
Consolidated total assets	30,100.2	27,908.8
LIABILITIES AND EQUITY
Long-term debt	5,194.5	4,909.7
Debt (Note 15)	5,157.8	4,896.1
Equity conversion feature of preferred stock (Note 6 and Note 16)		330.8
Deferred tax liabilities (Note 21)	533.3	492.8
Other liabilities	817.8	718.0
Total liabilities	27,843.2	26,445.9
Stockholders’ equity:
Common stock, $0.01 par; 500,000.0 thousand shares authorized; 202,295.6 thousand and 142,381.1 thousand shares issued and outstanding at September 30, 2014 and 2013, respectively.	2.0	1.4
Accumulated deficit	(276.3)	(192.4)
Accumulated other comprehensive income	243.6	87.7
Total permanent equity	2,257.0	1,133.5	1,598.9	1,373.0
Total liabilities and equity	30,100.2	27,908.8
HGI
ASSETS
Cash and cash equivalents	420.0	256.9	235.8	134.8
Receivables, net	42.5	41.0
Prepaid expenses and other current assets	0	3.3
Total current assets	462.5	301.2
Investments in subsidiaries and affiliates	2,357.4	2,049.0
Advances to consolidated subsidiaries	9.6	9.5
Properties, net	0.6	0.5
Deferred charges and other assets	31.6	23.1
Consolidated total assets	2,861.7	2,383.3
LIABILITIES AND EQUITY
Accounts payable	3.0	1.4
Accrued and other current liabilities	86.7	69.6
Total current liabilities	89.7	71.0
Long-term debt	1,354.4	924.2
Debt (Note 15)	1,325.0
Equity conversion feature of preferred stock (Note 6 and Note 16)	0	330.8
Employee benefit obligations	4.3	3.0
Other liabilities	1.1	0.3
Total liabilities	1,420.1	1,329.3
Temporary equity
Redeemable preferred stock	0	329.3
Stockholders’ equity:
Common stock, $0.01 par; 500,000.0 thousand shares authorized; 202,295.6 thousand and 142,381.1 thousand shares issued and outstanding at September 30, 2014 and 2013, respectively.	2.0	1.4
Additional paid-in capital	1,472.3	828.0
Accumulated deficit	(276.3)	(192.4)
Accumulated other comprehensive income	243.6	87.7
Total permanent equity	1,441.6	724.7
Total liabilities and equity	$ 2,861.7	$ 2,383.3