Stock Incentive Plans - Components of Pre-Tax Stock-Based Compensation Expense Included in Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Mar. 31, 2023	[1]	Mar. 31, 2022	[2]	Mar. 31, 2023	[1]	Mar. 31, 2022	[2]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 6		$ 5		$ 14		$ 11
Nonvested Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	4		2		7		6
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2		$ 3		$ 7		$ 5

[1] Included $1 million and $2 million of expense related to cash-settled nonvested restricted stock awards during the three and six months ended March 31, 2023.

[2] Included zero and $2 million of expense related to cash-settled nonvested restricted stock awards during the three and six months ended March 31, 2022.