Wells Fargo & Co. will pay $100 million to Citigroup Inc. to settle a heated fight between two of the nation’s biggest banks that began when Wells managed to sweep a stumbling Wachovia Corp. away from Citi’s grasp at the height of the 2008 banking crisis. Citi’s lawsuit over Wachovia, in New York state court, had roots in late-night deal-making sessions, when Wall Street’s banks teetered on the brink of demise and some of the biggest deals in banking history were forged in hours instead of days. The duel went back and forth, with Wells Fargo and Citi each seeking to win over Wachovia.