Retirement Benefits - Pension Plan Weighted Average Asset Allocations (Details) - Pension Benefits	Dec. 31, 2020	Dec. 31, 2019
U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	100.00%	100.00%
U.S. Plans | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	7.00%	10.00%
U.S. Plans | Fixed Income Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	65.00%	90.00%
U.S. Plans | Cash/Commingled Funds/Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	28.00%	0.00%
Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	100.00%	100.00%
Non-U.S. Plans | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	17.00%	17.00%
Non-U.S. Plans | Fixed Income Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	24.00%	24.00%
Non-U.S. Plans | Cash/Commingled Funds/Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan securities	59.00%	59.00%