Equity-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	9 Months Ended			1 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended	0 Months Ended			12 Months Ended		9 Months Ended
	Jun. 18, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 2013 Worldwide Equity Plan [Member]	May 31, 2013 Partnership Restricted Equity Units [Member]	Sep. 30, 2013 Partnership Restricted Equity Units [Member]	May 31, 2013 Restricted Share Units [Member]	Sep. 30, 2013 Restricted Share Units [Member]	Apr. 15, 2015 Restricted Share Units [Member] Scenario, Forecast [Member]	Sep. 30, 2013 Time Based [Member]	Sep. 30, 2013 Performance Based [Member]	Dec. 31, 2011 Worldwide Equity Plan [Member]	Sep. 30, 2013 Worldwide Equity Plan [Member]	Sep. 30, 2013 Worldwide Equity Plan [Member] Restricted Share Units [Member]	Sep. 30, 2013 Worldwide Equity Plan [Member] Partnership Restricted Share Units [Member]	Sep. 30, 2013 Worldwide Equity Plan [Member] Options [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized to grant				84.1		120.0
Remaining outstanding authorized shares vested					18
Equity compensation expense		$ 4	$ 2			$ 1									$ 2	$ 1
Grant date fair value, per share						$ 0.06								$ 0.37	$ 0.37
Parent company's indirect shareholding in the Company, percentage												100.00%
Shares granted and vesting description				In May 2013, 75.7 million RSUs were granted to employees, with two-thirds, or 50.5 million RSUs vesting one-sixth semi-annually on April 15 and October 15 each year for a period of three years, if the employee continues to remain in employment. The balance of one-third of the RSUs or 25.2 million, vest on April 15, 2015 upon satisfaction of certain performance conditions. As the performance conditions have not been communicated to the employees, these 25.2 million RSUs have not been considered as granted for accounting purposes.
Granted shares		50.5					75.7							50.6
Shares not considered as granted for accounting purposes									25.2
Options granted	4
Vesting period		3 years						3 years
Options vesting										2	2
Stock options contractual life		5 years
Grant date fair value of options													$ 0.12
Compensation expense resulted in credit to equity		3
Future equity-based compensation expense													$ 17