Share Repurchases (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2018	Mar. 31, 2017
Share Repurchases [Line Items]
Shares of common stock repurchased								147
Value of common stock repurchased								$ 8,683
Share Repurchase Program 2016
Share Repurchases [Line Items]
Shares of common stock repurchased	34	22	22	25			78
Value of common stock repurchased	$ 3,100	$ 1,800	$ 1,600	$ 1,600			$ 6,500
Share Repurchase Program 2013
Share Repurchases [Line Items]
Shares of common stock repurchased					59	63
Value of common stock repurchased					$ 3,533	$ 3,550