Employee Benefit Plans - Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,718		$ 2,711		$ 1,655
Domestic Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,302	[1]	1,293	[1]
Domestic Pension Plans [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,306	[1]	1,301	[1]
Domestic Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	110	[1]	117	[1]
Domestic Pension Plans [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	69		80
Domestic Pension Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	15	[1]	2	[1]
Domestic Pension Plans [Member] | Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	54	[1]	78	[1]
Domestic Pension Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | US Treasury Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	166		129
Domestic Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	166	[1]	129	[1]
Domestic Pension Plans [Member] | US Treasury Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Foreign Government Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	11		4
Domestic Pension Plans [Member] | Foreign Government Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Foreign Government Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	11	[1]	4	[1]
Domestic Pension Plans [Member] | Foreign Government Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	268		242
Domestic Pension Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	268	[1]	242	[1]
Domestic Pension Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	27		28
Domestic Pension Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Municipal Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	27	[1]	28	[1]
Domestic Pension Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	94		132
Domestic Pension Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	94	[1]	132	[1]
Domestic Pension Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Domestic equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	698		709
Domestic Pension Plans [Member] | Domestic equity securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	698	[1]	709	[1]
Domestic Pension Plans [Member] | Domestic equity securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Domestic equity securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Foreign Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	122		133
Domestic Pension Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	122	[1]	133	[1]
Domestic Pension Plans [Member] | Foreign Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,153	[2]	1,137	[2]
Percentage of Investment Funds Comprised Of Equity Securitites	61.00%		60.00%
Percentage of Investment Funds Comprised Of Debt Securities	39.00%		40.00%
Percentage Of Investment Funds Invested in United States Securities	64.00%		65.00%
Percentage Of Investment Funds Invested In International Securities	36.00%		35.00%
Domestic Pension Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	301	[1],[2]	320	[1],[2]
Domestic Pension Plans [Member] | Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	852	[1],[2]	817	[1],[2]
Domestic Pension Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[2]	0	[1],[2]
Domestic Pension Plans [Member] | Limited Partnership Interests [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	70	[3]	86	[3]
Domestic Pension Plans [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[3]	0	[1],[3]
Domestic Pension Plans [Member] | Limited Partnership Interests [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[3]	0	[1],[3]
Domestic Pension Plans [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	70	[1],[3]	86	[1],[3]	96	71
Domestic Pension Plans [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	40		31
Domestic Pension Plans [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Real Estate Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Pension Plans [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	40	[1]	31	[1]	26	24
Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	858		852		650
Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	613	[1]	614	[1]
Domestic Other Postretirement Plans [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	240	[1]	232	[1]
Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5	[1]	6	[1]
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	146	[4]	9
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	145	[1],[4]	5	[1]
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1	[1],[4]	4	[1]
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[4]	0	[1]
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	17		11
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	17	[1]	11	[1]
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	34		18
Domestic Other Postretirement Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	34	[1]	18	[1]
Domestic Other Postretirement Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	43		38
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	43	[1]	38	[1]
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	31		19
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	31	[1]	19	[1]
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Domestic equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	243		294
Domestic Other Postretirement Plans [Member] | Domestic equity securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	243	[1]	294	[1]
Domestic Other Postretirement Plans [Member] | Domestic equity securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Domestic equity securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6		8
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6	[1]	8	[1]
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Domestic Other Postretirement Plans [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	333	[5]	449	[5]
Percentage of Investment Funds Comprised Of Equity Securitites	63.00%		57.00%
Percentage of Investment Funds Comprised Of Debt Securities	37.00%		43.00%
Percentage Of Investment Funds Invested in United States Securities	69.00%		72.00%
Percentage Of Investment Funds Invested In International Securities	31.00%		28.00%
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	202	[1],[5]	296	[1],[5]
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	131	[1],[5]	153	[1],[5]
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[5]	0	[1],[5]
Domestic Other Postretirement Plans [Member] | Limited Partnership Interests [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5	[3]	6	[3]
Domestic Other Postretirement Plans [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[3]	0	[1],[3]
Domestic Other Postretirement Plans [Member] | Limited Partnership Interests [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[3]	0	[1],[3]
Domestic Other Postretirement Plans [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5	[1],[3]	6	[1],[3]	7	6
UK Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,368		2,177		1,996
UK Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	609	[1]	525	[1]
UK Pension Plans [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,560	[1]	1,473	[1]
UK Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	199	[1]	179	[1]
UK Pension Plans [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	43		23
UK Pension Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	43	[1]	23	[1]
UK Pension Plans [Member] | Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | US Treasury Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets			5
UK Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets			5	[1]
UK Pension Plans [Member] | US Treasury Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets			0	[1]
UK Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets			0	[1]
UK Pension Plans [Member] | United Kingdom Government Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	452
UK Pension Plans [Member] | United Kingdom Government Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	452	[1]
UK Pension Plans [Member] | United Kingdom Government Obligations [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]
UK Pension Plans [Member] | United Kingdom Government Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]
UK Pension Plans [Member] | Foreign Government Debt, Excluding That Of The United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	14		2
UK Pension Plans [Member] | Foreign Government Debt, Excluding That Of The United Kingdom [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Foreign Government Debt, Excluding That Of The United Kingdom [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	14	[1]	2	[1]
UK Pension Plans [Member] | Foreign Government Debt, Excluding That Of The United Kingdom [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	196		206
UK Pension Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	196	[1]	206	[1]
UK Pension Plans [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,464	[6]	1,387	[6]
Percentage of Investment Funds Comprised Of Equity Securitites	44.00%		45.00%
Percentage of Investment Funds Comprised Of Debt Securities	56.00%		55.00%
UK Pension Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	114	[1],[6]	122	[1],[6]
UK Pension Plans [Member] | Equity Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,350	[1],[6]	1,265	[1],[6]
UK Pension Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1],[6]	0	[1],[6]
UK Pension Plans [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	199		179
UK Pension Plans [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Real Estate Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
UK Pension Plans [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 199	[1]	$ 179	[1]	$ 163	$ 158

[1] Refer to Note 15 for additional discussion regarding the three levels of the fair value hierarchy.

[2] Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 61% and 39%, respectively, for 2014 and 60% and 40%, respectively, for 2013. Additionally, these funds are invested in United States and international securities of approximately 64% and 36%, respectively, for 2014 and 65% and 35%, respectively, for 2013.

[3] Limited partnership interests include several funds that invest primarily in buyout, growth equity and venture capital.

[4] In December 2014, PacifiCorp began to migrate funds to cash and cash equivalents in anticipation of the $150 million to be transferred to the UMWA in June 2015 as a result of the other postretirement settlement. Remaining investments were rebalanced to align to PacifiCorp's target investment allocations.

[5] Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 63% and 37%, respectively, for 2014 and 57% and 43%, respectively, for 2013. Additionally, these funds are invested in United States and international securities of approximately 69% and 31%, respectively, for 2014 and 72% and 28%, respectively, for 2013.

[6] Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 44% and 56%, respectively, for 2014 and 45% and 55%, respectively, for 2013.