Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Basic And Diluted [Abstract]
Net income (loss) available for common shareholders (A)	$ (6,302)	$ 6,267	$ 274	$ 11,934
Weighted average outstanding shares of common stock (B)	7,710	7,755	7,709	7,772
Dilutive effect of stock-based awards	0	75	90	81
Common stock and common stock equivalents (C)	7,710	7,830	7,799	7,853
Earnings (Loss) Per Share
Basic (A/B)	$ (0.82)	$ 0.81	$ 0.04	$ 1.54
Diluted (A/C)	$ (0.82)	$ 0.80	$ 0.04	$ 1.52