Procter & Gamble is increasing the prices of its powder and liquid laundry detergent products in the U.S. by an average of 6.4%, effective Sept. 18.The increased prices that the company will charge wholesalers will offset higher costs of raw materials and product research, company spokeswoman Molly Humbert said. P&G does not set retail prices but anticipates similar price increases at the retail level, she said.The price increases affect Tide, Cheer, Gain, Era and Bold brands. The incr...