CREATE TABLE customers (customer_id NUMBER, customer_details CLOB)
CREATE TABLE claims (claim_id NUMBER, policy_id NUMBER, date_claim_made TIME, date_claim_settled TIME, amount_claimed NUMBER, amount_settled NUMBER)
CREATE TABLE payments (payment_id NUMBER, settlement_id NUMBER, payment_method_code CLOB, date_payment_made TIME, amount_payment NUMBER)
CREATE TABLE settlements (settlement_id NUMBER, claim_id NUMBER, date_claim_made TIME, date_claim_settled TIME, amount_claimed NUMBER, amount_settled NUMBER, customer_policy_id NUMBER)
CREATE TABLE customer_policies (policy_id NUMBER, customer_id NUMBER, policy_type_code CLOB, start_date TIME, end_date TIME)

Which customers do not have any policies? Find the details of these customers.
SELECT customer_details FROM customers EXCEPT SELECT T1.customer_details FROM customers AS T1 JOIN customer_policies AS T2 ON T1.customer_id = T2.customer_id
SELECT "customer_details" FROM "customers" EXCEPT SELECT "T1"."customer_details" FROM "customers" "T1" JOIN "customer_policies" "T2" ON "T1"."customer_id" = "T2"."customer_id"