Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Oct. 12, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Nov. 01, 2017
Subsequent Event [Line Items]
Dividends declared per share (in US dollars per share)		$ 0.47	$ 0.43	$ 1.41	$ 1.30
Subsequent Event
Subsequent Event [Line Items]
Dividends declared per share (in US dollars per share)	$ 0.47
Assets Of One Of CEC Entities | Subsequent Event
Subsequent Event [Line Items]
Sale price						$ 5