2010
Democrats: 10 (=)
Republicans: 23 (=)
Write-In: 1 (=)
Republicans gain only 5 seats instead of 6, but that's only because they had overachieved in 2004 compared to RL results. This is still very much a landslide. In RG, John Cornyn unseats a longtime (and presumably Blue Dog-type) Dem incumbent amid very low Hispanic turnout. Presumably a similar thing happens in California with the last remnants of old-style Democratic populism. Loretta Sanchez face a serious challenge but hangs on, while Patty Murray resists much more easily than IRL. The NV race sees no change. Mark Kirk easily manages to fill the Republican open seat in IL. Rob Portman cruises in Ohio, but Sherrod Brown resists the wave in solidly Democratic ER. There's also obviously no pickup opportunity for the GOP in New York, but Johnson and Ellsworth's wins in WI and IN are even wider than IRL as a result of the border shifts. Finally, in Pennsylvania, Joe Sestak successfully primaries Republican-turned-Democrat Arlen Specter and proceeds to win a close race against Pat Toomey (sorry, Phil 
).
The 112th Senate (2011-2013)
Democrats: 52 (+1)
Republicans: 49 (+2)
Independents: 1 (-1) - Joe Lieberman, caucusing with Democrats
Note that Massachusetts is now purple because Brown still won the 2010 special election. This evens out with Specter's party switch and subsequent replacement with Sestak. Democrats still manage to keep control of the Senate, albeit only by only 4 seats instead of 6. The legislature would go largely as IRL.
Coats landslide Ellsworth IRL. Taking off the Democrat district would only make that landslide worse ITTL
