Details of sales for the years ended December 31, 2018, 2019 and 2020 are as follows:


		2018				2019				2020
		Domestic		Overseas		Domestic		Overseas		Domestic		Overseas
		In millions of won
[Type of goods and services]
Sales of goods	￦		57,514,866		382,938		56,609,330		285,546		56,380,608		303,704
Electricity			56,842,011		—		55,939,001		—		55,730,985		—
Heat supply			216,117		—		220,948		—		198,715		—
Others			456,738		382,938		449,381		285,546		450,908		303,704
Sales related to rendering of services			176,539		216,328		222,106		186,184		223,075		206,275
Sales of construction services			108,586		1,633,805		110,692		1,154,224		170,895		641,280

	￦		57,799,991		2,233,071		56,942,128		1,625,954		56,774,578		1,151,259

[Timing of revenue recognition]
Performance obligations satisfied at a point in time	￦		57,514,866		382,938		56,609,330		285,546		56,380,608		303,704
Performance obligations satisfied over time			285,125		1,850,133		332,798		1,340,408		393,970		847,555

	￦		57,799,991		2,233,071		56,942,128		1,625,954		56,774,578		1,151,259