Is my Spanish Social Security pension taxable if I am a resident of Spain?

I am a US citizen, permanent resident of Spain and receiving Social Security retirement pension paid by the Spanish Social Security system.

The US-Spain tax treaty reads as follows:

 (a) pensions and other similar remuneration derived and beneficially owned by a resident of a Contracting State in consideration of past employment shall be taxable only in that State; and

(b) social security benefits paid by a Contracting State to a resident of the other Contracting State or a citizen of the United States may be taxed in the first-mentioned State.

According to that, I understand that Spanish Social Security retirement pension, while residing in Spain, is not taxable in the US and should not be included in 1040. Am I correct?