The following graph shows the 'generic' voter preference for the Democratic or Republican party, and does not specify candidates in individual districts. This number has historically been a good indicator of the electoral result for the House of Representatives. (It uses aggregate survey trends and historical data from RealClearPolitics)
House of Representatives
The House of Representatives will be elected in its entirety (435 seats) on November 6. In its current composition, the Republican Party leads with 238 Representatives over 192 for the Democratic Party. This is how the balance of power would look after the election (according to the surveys aggregated by RealClearPolitics).
218 seats needed for a majority
In the upcoming November elections, a total of 35 senators will be elected, a little more than a third of the Senate. In its current composition, the Republican Party hold a narrow lead 52-48 over the Democratic Party. According to the surveys aggregated by RealClearPolitics, this is how the balance of power would look after November:
51 seats needed for a majority
Of the 50 states, the Republican Party controls 33 governorships, the Democratic Party has only 16 and 1 state, Alaska, has an independent governor. In November, governors will be elected in 36 states. This is how the distribution of state governors would look after November (According to the surveys aggregated by RealClearPolitics):