Retirement Benefits - Fair Value Measurements of Pension and Postretirement Benefit Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Derivative, Fair Value, Net	$ (21)	$ 51
Derivative, Notional Amount	5,123	3,351
Net liabilities pending transactions excluded	$ 670	388
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Repurchase Agreements, Maturities	3
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Repurchase Agreements, Maturities	6
Pension Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 8,785	9,402	$ 9,521
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	9,455	9,790
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,665	3,071
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,807	2,097
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	17	10
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4,966	4,612
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	205	267
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	205	267
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,489	2,208
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,127	1,513
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1	1
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,361	694
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,532	1,475
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,333	1,291
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	199	184
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	32	42
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	32	42
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,567	1,801
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,551	1,792
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	16	9
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	643	867
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	25	79
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	618	788
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	3,774	4,185
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,333	1,291
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,807	2,097
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	16	9
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	618	788
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,249	1,166
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Equity Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,249	1,166
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	464	578
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	464	578
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	730	760
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	730	760
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Placement [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	544	626
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan, Defined Benefit [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	544	626
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,355	1,355	1,351
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,355	1,355
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	665	550
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	71	110
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	619	695
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	44	45
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	44	45
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	626	586
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	437	315
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1	1
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	188	270
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	52	69
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	18	15
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	34	54
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2	7
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2	7
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | State and Municipal Debt [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	32	44
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	32	44
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	430	385
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	166	175
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2	4
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Other Debt Obligations [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	262	206
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	516	505
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	184	190
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	70	109
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Debt Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	262	206
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	75	109
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Hedge Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	75	109
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	78	88
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Real Estate Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	78	88
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Private Placement [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	16	22
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefits Plan [Member] | Fair Value, Recurring [Member] | Private Placement [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	16	22
Pension and other post retirement benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Derivative, Notional Amount	41	59
Pension and other post retirement benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	17	10	12
Pension and other post retirement benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1	1	0
Pension and other post retirement benefit [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	16	9	$ 12
Pension and other post retirement benefit [Member] | Fair Value, Recurring [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	10,810	11,145
Pension and other post retirement benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	3,330	3,621
Pension and other post retirement benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,878	2,207
Pension and other post retirement benefit [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	17	10
Pension and other post retirement benefit [Member] | Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 5,585	$ 5,307