Equity Items - Additional Information (Details) - USD ($)	3 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Accelerated Share Repurchases [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.25	$ 0.25	$ 0.25	$ 0.225	$ 0.225
Common Stock, Dividends Declared, Paid	$ 16,000,000	$ 16,000,000	$ 16,000,000		$ 14,000,000
2018 Stock Repurchase Program [Member]
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount				$ 1,000,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 1,000,000,000