J.P. Morgan and Deutsche Bank have paid substantial sums to settle charges ranging from bribery to illegal foreclosures to abetting tax evasion. Ruling out the connivance of top executives raises an alarming question: Does Jamie Dimon, J.P. Morgan’s highly regarded CEO, have as little grasp of the exposures embedded in his bank’s nearly $80 billion derivatives book as Tony Hayward, the hapless ex-CEO of BP, had of the hazards of his company’s ill-fated rig in the Gulf of Mexico?