Finding difference in minutes between two date/time fields

[PowerBINoob24]

If got a column that I'm trying to calculate the number of minutes between to date/time fields.  I've currently got 

Time To Access = DATEDIFF('UniqueUsers'[First Access Time],'UniqueUsers'[Send Date].[Day],MINUTE).  The Time to Access Column is formatted at a whole number data type and returns values like -64561883 for a time date that is 19 minutes apart.

Any thoughts on what I am doing wrong?

[grandtotal · Accepted solution]

Make sure that both input columns are in datatime format.
Then try to remove the .[Day] part:

Time To Access = DATEDIFF('UniqueUsers'[First Access Time],'UniqueUsers'[Send Date],MINUTE)

[PowerBINoob24]

That was it....just ahd to remove the .DAY  Thanks!  It's the little things.....