Summary of accounting policies (Tables)

12 Months Ended

Mar. 31, 2019

Accounting Policies [Abstract]

Breakdown of Office buildings, land, equipment and facilities

	Millions of yen
	March 31
	2018		2019
Land	¥	67,103	¥	49,474
Office buildings		98,966		103,423
Equipment and facilities		45,164		75,206
Software		127,678		121,245
Construction in progress		73		17
Total	¥	338,984	¥	349,365

Schedule of estimated useful lives for significant asset classes

Office buildings	5 to 50 years
Equipment and facilities	2 to 20 years
Software	Up to 5 years