Retirement Benefit Plans (Actual Allocation Percentage and Target Allocation Percentage for the U.S. Pension Plan Assets) (Details) - Pension Plan	Dec. 31, 2020	Dec. 31, 2019
U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation	45.40%	45.10%
Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation	20.30%	20.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation	33.90%	34.40%
Money market
Defined Benefit Plan Disclosure [Line Items]
Actual allocation	0.40%	0.50%
Minimum | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	36.00%
Minimum | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	16.00%
Minimum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	30.00%
Minimum | Money market
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	0.00%
Maximum | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	54.00%
Maximum | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	24.00%
Maximum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	40.00%
Maximum | Money market
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	10.00%