Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income available for common shareholders (A)	$ 3,756	$ 5,018	$ 4,902	$ 4,985	$ 13,676	$ 15,388
Weighted average outstanding shares of common stock (B)	7,895			8,167	7,952	8,215
Dilutive effect of stock-based awards	90			70	89	78
Common stock and common stock equivalents (C)	7,985	8,051	8,084	8,237	8,041	8,293
Earnings Per Share
Basic (A/B)	$ 0.48	$ 0.63	$ 0.61	$ 0.61	$ 1.72	$ 1.87
Diluted (A/C)	$ 0.47	$ 0.62	$ 0.61	$ 0.61	$ 1.70	$ 1.86