Benefit Obligations (Schedule of Company Commitments to Fund Benefit Obligations) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	$ 2	[1]
Total expected contributions in current fiscal year	6	[1]
Cash Contributions to Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	21
Total expected contributions in current fiscal year	26
Other Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	6
Total expected contributions in current fiscal year	22
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions year-to-date	2
Total expected contributions in current fiscal year	$ 17

[1] The Company makes contributions based on specified percentages of employee contributions.