With rent, what gets taxed?

[Stephen Shelton]

I have a question on what gets taxed when it comes to rental income.  Of course there are loads of other factors but I'm looking for general answers for someone living in the US without state income taxes.

For example, say I have a single-family home bought for the purpose of being a rental property that works as follows:

Rent: $1000 month / $12,000 annual

And it breaks down like this:

$2000 - property tax

$2000 - insurance

$2000 - mortgage principal

$2000 - mortgage interest

$2000 - repairs

$2000 - unused/profit

Which pieces are taxed? Would the property taxes, insurance, mortgage interest, and repairs be considered untaxable business expenses? 

I assume the final unused/profit $2000 would be taxed like regular income, but what about the mortgage principal?  Since it represents owning the renter buying me a piece of the property itself is it considered income?

Thanks for some clarity