Retirement and Other Postretirement Benefit Plans - Schedule of Actual Allocations for the Pension Assets and Target Allocations by Asset Class (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	100.00%	100.00%
Target allocations by asset class (as a percent)	100.00%	100.00%
Diversified Growth Funds
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	24.10%	27.60%
Target allocations by asset class (as a percent)	29.00%	27.00%
Liability Driven Investments
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	20.10%	22.30%
Target allocations by asset class (as a percent)	24.00%	22.00%
All Other Regions Equity Fund
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	18.70%	19.30%
Target allocations by asset class (as a percent)	34.00%	20.00%
U.K. Equity Fund
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	12.60%	13.00%
Target allocations by asset class (as a percent)		15.00%
Debt Securities
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)		8.70%
Target allocations by asset class (as a percent)		9.00%
Index Linked Gilts
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	21.10%	5.30%
Target allocations by asset class (as a percent)	13.00%	5.00%
Diversified Investment, Funds
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	1.20%	1.30%
Other Insurance Product Line
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	2.10%	2.20%
Target allocations by asset class (as a percent)		2.00%
Cash and Cash Equivalents
Change in plan assets:
Total plan assets invested in active corporate bond funds (as a percent)	0.10%	0.30%