The document discusses Aon Corporation implementing a notional cash pooling structure to address issues from the credit crisis. Aon is a global insurance broker with decentralized management and cash balances located outside the US while taking on debt in the US and UK. The notional cash pool provides cash visibility, self-funding abilities, and excess cash management across currencies and countries while reducing debt, counterparty exposure, and meeting annual dividend needs. It is managed from Amsterdam and excludes the US for tax reasons, providing transparency of balances and interest rates with limited access to accounts. The results have included debt management, self-funding, and reduced counterparty exposure through centralized excess cash management at Aon.