| Held-to-maturity Securities, Gross Gains (Losses), Derivatives (Deprecated 2018-01-31) | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Held-to-maturity Securities, Gross Gains (Losses), Derivatives, Total (Deprecated 2018-01-31) | en-US | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| This item represents, as of the balance sheet date, the gross gains and losses in accumulated other comprehensive income, a separate component of shareholders' equity, for any derivatives that hedged the forecasted acquisition of held-to-maturity securities. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |