Consolidated Statements of Financial Position (Parenthetical) $ in Millions	Sep. 30, 2017 € / shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 € / shares	Sep. 30, 2016 USD ($) $ / shares shares
Allowance for doubtful accounts | $		$ 182		$ 173
Ordinary shares, par value | $ / shares		$ 0.01		$ 0.01
Ordinary shares authorized		2,000,000,000		2,000,000,000
Ordinary shares issued		945,055,276		936,247,911
Preferred shares authorized		200,000		200,000
Preferred shares issued		0		0
Preferred shares, par or stated value per share | $ / shares		$ 0.01		$ 0.01
Ordinary shares held in treasury, as cost		17,080,302		452,083
Common Class A [Member]
Ordinary shares, par value | € / shares	€ 1.00		€ 1.00
Ordinary shares authorized		40,000		40,000
Ordinary shares issued		0		0