So I've always wondered about Google's market cap after the split. If class C (GOOG) is worth $495B and class A $495B shouldn't Google be worth $990B or am I getting it wrong?
You are right: if the combined value of all outstanding GOOG shares was $495B, and the combined value of all GOOGL shares was $495B, then yes, Alphabet would have a market cap of at least $990B (where I say at least only because I myself don't know that there aren't other issues that should be in the count as well).
The respective values of the total outstanding GOOG and GOOGL shares are significantly less than that at present though. Using numbers I just grabbed for those tickers from Google Finance (of course), they currently stand thus:
Ticker Price Shares Outstanding (M) Market Cap (B) GOOGL 717.51 * 292.3 = 209.73 GOOG 697.35 * 344.76 = 240.42 ------ 450.15