cloud nine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A state of elation or great happiness.

from the GNU version of the Collaborative International Dictionary of English.

• noun a state of extreme or perfect happiness; used especially in the phrase on cloud nine.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun idiomatic A state of happiness, elation or bliss; often used in the phrase on cloud nine

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a state of extreme happiness