NEW YORK (Reuters) - Aon Corp (AOC.N: Quote, Profile, Research) one of the world's largest insurance brokers by market capitalization, said on Thursday that net income fell 7 percent in the fourth quarter, and announced a shake up to its business structure.

Net earnings were $207 million or 64 cents a share, down from $223 million or 67 cents a share in the year earlier quarter.

Net income from continuing operations, excluding certain items, increased 17 percent to 69 cents compared to 59 cents for the prior year quarter, ahead of Wall Street expectations.

Revenue rose 8 percent to $2 billion.

Analysts had on average expected earnings of 67 cents a share on revenue of $1.95 billion.

Restructuring expense was $34 million in the fourth quarter compared to $78 million in the prior year quarter, Aon said.

Separately, the Chicago-based company said it was integrating its worldwide risk and insurance brokerage operations into a single entity, Aon Risk Services.

Its board also increased authorization for share buybacks by $2.6 billion, a move that the company had already said it planned. It will use proceeds from the $2.75 billion sale of two units to Ace Limited (ACE.N: Quote, Profile, Research) and Munich Re (MUVGn.DE: Quote, Profile, Research), which was announced in December.

(Reporting by Lilla Zuill; editing by Carol Bishopric, Leslie Gevirtz)