How many members of Congress does it take to count to a billion?

The top 12. At least according to The Hill's annual calculation of the 50 wealthiest members. Newly topped out by California Rep. Darrell Issa's $355.4 million, adding up his wealth with the next 11 richest of his compatriots totals $1.02 billion.

Issa, chairman of the House Oversight Committee and self-described Republican watchdog of the Obama administration, this year beat out Texas Republican Rep. Michael McCaul, last year's richest member of Congress. For his part, McCaul is worth $101.9 million, most of which comes from family trusts.

According to The Hill, Issa's wealth ballooned a few zeroes after he shed some $75 million in liabilities last year. With several huge investment funds worth as much as $50 million apiece, Issa's wealth comes from his role in founding Directed Electronics, creator of the Viper anti-theft system for cars.

Issa, McCaul and their fellow Republicans make up 29 of the 50 richest members of Congress. Republicans have held a majority in the wealth category for three years now. Most of the top 50 list comes from the lower chamber, with 37 in the House of Representatives and 13 in the U.S. Senate.

While the first two richest are Republicans, spot number three goes to a Democrat, Sen. Mark Warner of Virginia. A tech investor, he's worth $88.5 million.

Worth noting, wealth reported by The Hill represents the minimum net worth of each member of Congress, since they are only required to report ranges. The Hill's calculation was based on the lower value of the reporting range, meaning each member could be worth more than the value ascribed to them and it could take far less than 12 to count to $1 billion.