Equity and Noncontrolling Interests Equity Attributable to Johnson Controls, Inc. and Noncontrolling Interests (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Proceeds from Sale of Available-for-sale Securities, Equity			$ 25
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value				$ 691
Stock Repurchase Program, Authorized Amount	$ 3,650
Cash dividends common, per share	$ 1.16	$ 1.04	$ 0.88
Repurchases of common stock	$ 501	$ 1,362	$ 1,249
Available-for-sale Securities, Gross Realized Gains			$ 8