Income Taxes (Reconciliation of Effective Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Expected tax rate	7.80%	7.80%	7.80%
Income not subject to income tax	(7.10%)	(8.20%)	(7.30%)
Foreign taxes at local expected tax rates	4.40%	1.40%	2.10%
Disallowed expenses and capital allowances	0.20%	1.00%	0.70%
Prior year refunds and adjustments	1.20%	0.80%	0.40%
Other	(0.60%)	(0.50%)	(0.10%)
Effective tax rate	5.90%	2.30%	3.60%