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

List the details of the customers who do not have any policies.
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" AS "T1" JOIN "customer_policies" AS "T2" ON "T1"."customer_id" = "T2"."customer_id"